New lfx engine

[iPODFAN11]

Originally Posted by arkentect

have you replaced all your spark plugs and sparkplug wires? My last car was misfiring on a few cylinders because one of the wires was shorting out.

Tell me please...you own an LLT car yet you know nothing about it?

LLT and LFX have no spark plug wires. Coil over plug. You crap a boot on the coil, you put a coil assembly on it. Nice try kid.

[jd10013]

Originally Posted by Red2014SS

Keep in mind that he leased this car. That means he only paid to use it for so many years/miles. When he returns it, it needs to be worth the agreed upon value at the time of lease. A car with a used/replaced engine is not what the dealership will be expecting come end of lease. It will hurt the resale value of that car, and they'll expect him to cough up the difference or buy the car.

I would fix the engine that's already in it. I think the dealership is trying to rip him off instead of fixing the car.

this. the dealership will also have an issue with the VIN's on the car and engine not matching. even with a crate engine that will lower the value of the car. best to fix whats in there.

[jd10013]

Originally Posted by iPODFAN11

Tell me please...you own an LLT car yet you know nothing about it?

LLT and LFX have no spark plug wires. Coil over plug. You crap a boot on the coil, you put a coil assembly on it. Nice try kid.

everything is coil over plug now. the days of distributors, points, etc have been over for 20 years.

[iPODFAN11]

Originally Posted by jd10013

everything is coil over plug now. the days of distributors, points, etc have been over for 20 years.

I am fully aware...my post was in reference to a response...

[United_727]

Originally Posted by arkentect

have you replaced all your spark plugs and sparkplug wires? My last car was misfiring on a few cylinders because one of the wires was shorting out.

V6's don't have plug wires

[TPAJETSKI]

Originally Posted by iPODFAN11

Tell me please...you own an LLT car yet you know nothing about it?

LLT and LFX have no spark plug wires. Coil over plug. You crap a boot on the coil, you put a coil assembly on it. Nice try kid.

He did say his "last car". Maybe that one had wires and was just offering general advice....

EDIT: I'm not commenting on whether his general advice was any good.

[Russell James]

A plugged cat can wipe out an engine pretty quick. As it is disentegrating exhaust reversion and back pressure can blast that debris back up into the engine.

If one bank is misfiring, and that's the bank that had the plugged cat. Time to do a leak down test, and look at the plugs close for aluminum speckles.

If that side has high leak down and speckled spark plugs, that's all she wrote for that motor.

Clean plugs, good compression and leakdown... then it would be worth it to investigate further was is causing the misfiring.

Can also let it idle with the oil cap off. If it's puffing compression puffs out the oil fill hole, call the Priest in for last rights.

But cats just don't melt and plug nice and cleanly. They go into thermonuclear melt down from an AFR problem, and as melting... engine destroying crap is going everywhere.

GM has a bulletin that advises techs when a damaged cat converter is found, check for engine damage. It would be quite rare to find a perfect condition engine connected to a melted cat.

[TommyTheCat]

Originally Posted by moE_09

First off I just wanna say thanks for the all the input and advice, I really appreciate it. And the facotry tune is on, the dealer said they tested for hydro carbon? And said it was fine. But I can smell antifreeze in the cabin. And this whole issue started when I first got the car. From nov of 2013 till about January or feb they couldn't figure out what was wrong. Then eventually they realzied there was tsb out for the misfire under accerlstion. So got that fixed. Started modding skip to December of 2014 car was working fine. Had all my mods installed. day before Christmas Eve I get on and start my car n get a service stabitrak n it starts sounding werid. Like sometbing is clogged. I ask go around asking ppl bc I think it's my hi flo cats and everybody tells me no can't be. I take of my manifold spacer bc people r saying it could cause a vaccume leak. Doesn't fix the issue. I finally get a scanner and realzir cylinder 6 is misfiring. ( worst mistake here) people tell me it's bc of the cold. So I let it be. It goes away and comes back mid march, I start hearing a loud rattle and cyl1-6 misfire. And normally my coolant temp is 180 and same with my oil temp. Now it doesn't go below 195. And if I let it idle it'll rise upto 220. I tske off my hi flo cats bc I started getting readings for a low 02 sensor. And realzied they got clogged. I ship them back to solo and they tell me the cats r complety torched. After the cats were taking off the car only misfired on cyl 2,4,6. So on the Same bank, rn mostly it's only on 2,6. Very little on cyl 4. And I get the service stabitrak light. I have the facotry tune on it and factory cats

Edit: just checked my oil dipstick. Seems a little to dry,I don't see anything leaking but dryer than it's been in the past. I just got an oil chnage maybe less than 500 miles ago

Okay everything in red is pretty important. The stabilitrak light will always come on with a misfire on our cars. A misfire (which you had) will ruin catalytic converters, melting them apart, and clogged cats will also cause lack of power or even hard/no start conditions. I would take off the stock cats for now until the problem is corrected, or else you may have to fix those as well (if they aren't already melted)

Misfire because of the cold? Never. This is 2015... direct fuel injection. Tell that guy who told you the cold will cause a misfire, especially on a single cylinder, he's an idiot. It won't.

220 and 195 degrees is not overheating. If you're not getting passed the center of the ECT gauge, you're still good.

Smelling antifreeze in the cabin? Are you losing coolant? This is not a head blown gasket symptom... This is a symptom of a leaking heater core! Does your windshield fog up easily? This should be covered under warranty, NO EXCUSE. None of your mods could have affected this! Or the blown off coolant hose.

PM me for more info, you definitely should NOT replace the engine. None of these symptoms resemble an engine problem anyways. Have the compression checked, swap the coils from 2,4,6 to 1,3,5. If anything you might need a valve job just because the misfire seems to only be coming from bank 2, but there are plenty of other factors that can cause single banked misfires. Most likely not injectors, plugs or coils, but if you swap coils and plugs you can at least guarantee that they're not the problem if the misfire stays on the same cylinders. Get me?

Carbon build up is also a common issue on our cars, along with every other direct injection vehicle. Do you have a catch can installed?

And if the oil is low make sure you top it off. If you change it yourself, the LFX and LLT take 6 quarts of oil while the LS3/L99 should take I believe 7. Make sure not to mix those two, and some dealers/mechanics may do that as well. Also if you go to hole in the wall shops or walmart for your oil change, they may only cover 4-5 quarts of oil at their cheap prices, which is not enough. Never go there, walmart sends my shop work every week for blowing engines up, leaving drain plugs off, loose oil filters, blown fuses/computers from connecting batteries backwards... Even see tires installed backwards. (the tread)

PM me for more info. If you were in CA I'd help you out to diagnose. Get a chemical block tester from NAPA or something to check for the head gasket problem, which I don't believe you have.


NOW to make sure you don't overheat and cause further problems, make sure your radiator is full of water and the reservoir as well. Just water is fine for now while you figure out the problem or you'll keep spending cash on coolant that might be leaking inside the cab due to a heater core problem.
Take off the engine cover

Originally Posted by JR 1

Yeah, if I was going to replace an engine I would get a low mileage used engine. Reman is probably an option too considering how common the LXF engine is.

Reman is usually almost as expensive as a new engine.

Originally Posted by jd10013

everything is coil over plug now. the days of distributors, points, etc have been over for 20 years.

points... lol those have been gone way longer than 20 years I assure you. surprised I'm not the only one who still remembers those

[jd10013]

Originally Posted by TommyTheCat

points... lol those have been gone way longer than 20 years I assure you. surprised I'm not the only one who still remembers those

points yes, distributors no

[DP Valentino]

Originally Posted by Sales @ CAI Inc

Good advice here.

Live and learn, personally I have never heard of modding a leased car that much, especially tuning one. I think that is where they got you on not covering the warranty, which makes sense really. Good luck with the whole situation!!

The OP modified a LEASED car???

[moE_09]

Originally Posted by Russell James

A plugged cat can wipe out an engine pretty quick. As it is disentegrating exhaust reversion and back pressure can blast that debris back up into the engine.

If one bank is misfiring, and that's the bank that had the plugged cat. Time to do a leak down test, and look at the plugs close for aluminum speckles.

If that side has high leak down and speckled spark plugs, that's all she wrote for that motor.

Clean plugs, good compression and leakdown... then it would be worth it to investigate further was is causing the misfiring.

Can also let it idle with the oil cap off. If it's puffing compression puffs out the oil fill hole, call the Priest in for last rights.

But cats just don't melt and plug nice and cleanly. They go into thermonuclear melt down from an AFR problem, and as melting... engine destroying crap is going everywhere.

GM has a bulletin that advises techs when a damaged cat converter is found, check for engine damage. It would be quite rare to find a perfect condition engine connected to a melted cat.

Originally Posted by TommyTheCat

Okay everything in red is pretty important. The stabilitrak light will always come on with a misfire on our cars. A misfire (which you had) will ruin catalytic converters, melting them apart, and clogged cats will also cause lack of power or even hard/no start conditions. I would take off the stock cats for now until the problem is corrected, or else you may have to fix those as well (if they aren't already melted)

Misfire because of the cold? Never. This is 2015... direct fuel injection. Tell that guy who told you the cold will cause a misfire, especially on a single cylinder, he's an idiot. It won't.

220 and 195 degrees is not overheating. If you're not getting passed the center of the ECT gauge, you're still good.

Smelling antifreeze in the cabin? Are you losing coolant? This is not a head blown gasket symptom... This is a symptom of a leaking heater core! Does your windshield fog up easily? This should be covered under warranty, NO EXCUSE. None of your mods could have affected this! Or the blown off coolant hose.

PM me for more info, you definitely should NOT replace the engine. None of these symptoms resemble an engine problem anyways. Have the compression checked, swap the coils from 2,4,6 to 1,3,5. If anything you might need a valve job just because the misfire seems to only be coming from bank 2, but there are plenty of other factors that can cause single banked misfires. Most likely not injectors, plugs or coils, but if you swap coils and plugs you can at least guarantee that they're not the problem if the misfire stays on the same cylinders. Get me?

Carbon build up is also a common issue on our cars, along with every other direct injection vehicle. Do you have a catch can installed?

And if the oil is low make sure you top it off. If you change it yourself, the LFX and LLT take 6 quarts of oil while the LS3/L99 should take I believe 7. Make sure not to mix those two, and some dealers/mechanics may do that as well. Also if you go to hole in the wall shops or walmart for your oil change, they may only cover 4-5 quarts of oil at their cheap prices, which is not enough. Never go there, walmart sends my shop work every week for blowing engines up, leaving drain plugs off, loose oil filters, blown fuses/computers from connecting batteries backwards... Even see tires installed backwards. (the tread)

PM me for more info. If you were in CA I'd help you out to diagnose. Get a chemical block tester from NAPA or something to check for the head gasket problem, which I don't believe you have.


NOW to make sure you don't overheat and cause further problems, make sure your radiator is full of water and the reservoir as well. Just water is fine for now while you figure out the problem or you'll keep spending cash on coolant that might be leaking inside the cab due to a heater core problem.
Take off the engine cover



Reman is usually almost as expensive as a new engine.

points... lol those have been gone way longer than 20 years I assure you. surprised I'm not the only one who still remembers those

That first post made me think I might need a new engine.
But thank you for such a detailed response tommy the cat. Just a few questions, when u say remove the engine cover u mean the plastic thig sitting on top correct ? What's the reason for that? Simply to extract heat better ? And yes the needle has never gotten above half but it's been close to half. On the highway on cruise control thou the coolant temp seems perfectly stable sitting at 180. Any other situation it'll be higher. I took off my VtC bc well it's prob not a good time to have that on the misfires don't happen as often bc I'm keeping in the lower rpms now. But I still feel a loss of a power and with my scan tool the misfires r much less, I do not have a catch can but the dealer said they did "carbon cleaning" and lately I've been checking since I re filled the resivor the leel seems to stay the same. But whenever I remove the radiator cap even after 10 mins of driving that thing will have smoke coming out from it and it's bubbling, I'll try the idle with the oil cap off and see what happens, so to fix it I should tell the dealer to start by switching around the coils, if it's still on the same bank that means my coils r fine and then proccesed by doing a compression test and a leak down test?

[maddoggyusa]

Originally Posted by TommyTheCat

Okay everything in red is pretty important. The stabilitrak light will always come on with a misfire on our cars. A misfire (which you had) will ruin catalytic converters, melting them apart, and clogged cats will also cause lack of power or even hard/no start conditions. I would take off the stock cats for now until the problem is corrected, or else you may have to fix those as well (if they aren't already melted)

Misfire because of the cold? Never. This is 2015... direct fuel injection. Tell that guy who told you the cold will cause a misfire, especially on a single cylinder, he's an idiot. It won't.

220 and 195 degrees is not overheating. If you're not getting passed the center of the ECT gauge, you're still good.

Smelling antifreeze in the cabin? Are you losing coolant? This is not a head blown gasket symptom... This is a symptom of a leaking heater core! Does your windshield fog up easily? This should be covered under warranty, NO EXCUSE. None of your mods could have affected this! Or the blown off coolant hose.

PM me for more info, you definitely should NOT replace the engine. None of these symptoms resemble an engine problem anyways. Have the compression checked, swap the coils from 2,4,6 to 1,3,5. If anything you might need a valve job just because the misfire seems to only be coming from bank 2, but there are plenty of other factors that can cause single banked misfires. Most likely not injectors, plugs or coils, but if you swap coils and plugs you can at least guarantee that they're not the problem if the misfire stays on the same cylinders. Get me?

Carbon build up is also a common issue on our cars, along with every other direct injection vehicle. Do you have a catch can installed?

And if the oil is low make sure you top it off. If you change it yourself, the LFX and LLT take 6 quarts of oil while the LS3/L99 should take I believe 7. Make sure not to mix those two, and some dealers/mechanics may do that as well. Also if you go to hole in the wall shops or walmart for your oil change, they may only cover 4-5 quarts of oil at their cheap prices, which is not enough. Never go there, walmart sends my shop work every week for blowing engines up, leaving drain plugs off, loose oil filters, blown fuses/computers from connecting batteries backwards... Even see tires installed backwards. (the tread)

PM me for more info. If you were in CA I'd help you out to diagnose. Get a chemical block tester from NAPA or something to check for the head gasket problem, which I don't believe you have.


NOW to make sure you don't overheat and cause further problems, make sure your radiator is full of water and the reservoir as well. Just water is fine for now while you figure out the problem or you'll keep spending cash on coolant that might be leaking inside the cab due to a heater core problem.
Take off the engine cover



Reman is usually almost as expensive as a new engine.

points... lol those have been gone way longer than 20 years I assure you. surprised I'm not the only one who still remembers those

TommytheCat... who died and made you the chief mechanic? Half of your rant is plain wrong... and I find it hilarious you calling out other people.

A few misfires won't kill your cats. A plugged cat killing your engine? Yea I'm sure there are some rare stories but I've replaced lots of plugged cats on engines and they're fine. Yes, the cold has caused lots of misfires in the Wintertime. There were lots of people on these boards this winter having problems. The problems went away.... probably caused by intermittent wiring/connector issues due to extreme cold temps. Smelling coolant in the cabin can mean a leak in the cooling system anywhere! Not just the heater core. Walmart isn't stupid enough to not put enough oil in your vehicle. Like almost all shops, you typically pay extra for more than 5 quarts.

You have some good advice mixed in with some nonsense.

[Destructo09]

In regards to modifying a leased vehicle, I once knew a guy who did a SAS (solid axle swap) on a leased Tacoma. Apparently they freaked out a bit when he brought it back, but he was planning on buying it after the lease term so it didn't matter lol.

I did enjoy the faces the dealer guys made though when he took it in at the end of the lease.

[Russell James]

How many miles? And how frequent were the oil changes?

A plugged cat can damage an engine, I've seen it a few times. GM even put out a bulletin. Started happening more often when cats moved very close to the engine. You're right though, it is rare, but possible.

Crudded up intake valves another possibility. Especially if the miles are getting up there and there has been less than frequent oil changes. Cruddy oil and a DI engine do not mix will, intakes can get carboned up.

If nothing turns up with the basic checks of ignition, fuel, sensors.... then look at the mechanicals with a leak down test. Then possibly remove the intake and look at the intake valves with a boroscope. A leak down test and look at the intake valves with a boroscope will tell a lot about the engines condition.