Car feels like it's sputtering under load (No check engine lights)

[DonM]

Coming into work, I was doing about 65 in 6th gear (about 2,000 RPMs). I accelerated without downshifting, and I could feel like a stuttering in the gas pedal. I tried the same thing in 5th and 4th with the same result. Nothing really bad, but definitely noticeable.

I have 72,300 miles, have had a K&N drop-in filter since roughly February 2016 (uncleaned so far, last time I looked it didn't appear too dirty).

I've never checked or changed the spark plugs or cleaned the MAF sensor.

Any ideas of where to start?

[ChibiBlackSheep]

Start with cleaning the MAF, and your throttle body. Do you run a catch-can?

Sounds like the car was leaning out on you.

Also take the time to check all of your electrical sensor connections. Make sure everything is nice and tight. If this doesn't work, it's time to pull some spark plugs and take a look.

[DonM]

No catch can and I plan on buying some MAF cleaner on the way home and doing it then. About the TB, do I HAVE to remove it to clean it or do I just spray some cleaner around the throat & butterfly & wipe it down with a clean rag? If I have to remove it, that's a project for the weekend ... same with pulling the plugs .... BTW - is there a How-To on plug replacement on an LFX? If they are questionable or bad, which kind should I get to replace them? They are factory installed.

Originally Posted by ChibiBlackSheep

Start with cleaning the MAF, and your throttle body. Do you run a catch-can?

Sounds like the car was leaning out on you.

Also take the time to check all of your electrical sensor connections. Make sure everything is nice and tight. If this doesn't work, it's time to pull some spark plugs and take a look.

[ChibiBlackSheep]

Originally Posted by DonM

No catch can and I plan on buying some MAF cleaner on the way home and doing it then. About the TB, do I HAVE to remove it to clean it or do I just spray some cleaner around the throat & butterfly & wipe it down with a clean rag? If I have to remove it, that's a project for the weekend ... same with pulling the plugs .... BTW - is there a How-To on plug replacement on an LFX? If they are questionable or bad, which kind should I get to replace them? They are factory installed.

You need to remove it to clean it. Super easy, it's just 4 10mm bolts and a quick disconnect of the sensor.

Without a catch can, you probably have a lot of carbon buildup that will need to be cleaned. Worth pricing around if you aren't comfortable doing it yourself.

For the plugs, check out this link: http://www.paulstravelpictures.com/G...ide/index.html

If they are bad, just replace with factory equivalent.

[DonM]

OK, I was wondering how to spray a bunch of cleaner into/around the TB without it going down the throat of the intake. I CAN do throttle body removal, it's removing the intake manifold & walnut blasting the valves that scares me. Any specific cleaner for the TB, it seems the only cleaner readily available for the MAF sensor is CRC.

Originally Posted by ChibiBlackSheep

You need to remove it to clean it. Super easy, it's just 4 10mm bolts and a quick disconnect of the sensor.

Without a catch can, you probably have a lot of carbon buildup that will need to be cleaned. Worth pricing around if you aren't comfortable doing it yourself.

For the plugs, check out this link: http://www.paulstravelpictures.com/G...ide/index.html

If they are bad, just replace with factory equivalent.

[ChibiBlackSheep]

Originally Posted by DonM

OK, I was wondering how to spray a bunch of cleaner into/around the TB without it going down the throat of the intake. I CAN do throttle body removal, it's removing the intake manifold & walnut blasting the valves that scares me. Any specific cleaner for the TB, it seems the only cleaner readily available for the MAF sensor is CRC.

CRC is good stuff, it's what I use. I would also just use the same on the TB and wipe it down with a cloth. The back of your TB will probably be caked with carbon, and you can imagine that's what the valves look like too.

I would really look into getting a catch-can (clean AND dirty side), and pricing out a shop to do the upper intake cleaning.

[DonM]

Originally Posted by ChibiBlackSheep

CRC is good stuff, it's what I use. I would also just use the same on the TB and wipe it down with a cloth. The back of your TB will probably be caked with carbon, and you can imagine that's what the valves look like too.

I would really look into getting a catch-can (clean AND dirty side), and pricing out a shop to do the upper intake cleaning.

I did price out a manual cleaning of the valves (removing the intake & new gaskets etc.) The shop I prefer to use likes to estimate high, so there are no surprises when the job is finished and it might even cost less than originally stated. Well, for them to do the manual cleaning (no walnut blasting, just SEA FOAM LIQUID and brushes) was estimated at $775.00. Too rich for me, when I can't even afford to get a catch can to prevent the valve coking.

[DSX_Camaro]

Stock clutch?

[ChibiBlackSheep]

Originally Posted by DonM

Too rich for me, when I can't even afford to get a catch can to prevent the valve coking.

That's unfortunate. Are you upside down on the car loan at all? I have seen horror stories from LFX owners after their drivetrain warranty expires of the engine shitting the bed. Since you are nearing that 80,000 mile mark and at 5 years depending on when you bought the car, I would start to worry about financing an issue like that.

I know financials are what they are, but if there's ANY way you can put aside a little money each month towards repairs, I don't trust the longevity of this engine anymore.

Or maybe try the manual cleaning. I haven't removed the UIM from my car yet, but I have read that it really isn't that tough to do.

[DonM]

Originally Posted by DSX_Camaro

Stock clutch?

Yea, stock (factory) clutch. It didn't feel like it was slipping, I a 1990 Plymouth Laser Turbo that the clutch went out on, so I know what slipping feels like. This was more like the engine was "lugging" because the trans was in too high of a gear for the speed & RPMs

[DonM]

Huh, it didn't act up on the way home at all, it just accelerated like normal. I'm STILL going to clean the MAF sensor, throttle body and K&N air filter. I might even pull the plugs.

[ChibiBlackSheep]

Originally Posted by DonM

Huh, it didn't act up on the way home at all, it just accelerated like normal. I'm STILL going to clean the MAF sensor, throttle body and K&N air filter. I might even pull the plugs.

Mine was funky too. It would do it every other week or so. Since I've taken it all apart and cleaned it though it's been doing well.

[12blkgrayRS]

I had the almost the same problem. Mine was low on power, see my thread in this area.
Replace MAF sensor first, helped, better response but then getting P0300 SELs. After testing the coils Cleaning the TB. I found 3 weak coils (idle was irradic and rough).
Replaced the coils. and spark plugs with Factory OEM iridium plugs. Reset the ECU.
Car now runs strong, and idle so smooth, I cant even tell it's running. Sounds like the engine wanted to jump out of the engine bay before. the only problem I am having now is the temp error stating it's turning off my a/c due to high eng temp. I just need to replace my tstat, which is stuck open. My next project, not an easy replacement, installed on the BACK of the engine! Stupid!

[DSX_Camaro]

Originally Posted by DonM

Yea, stock (factory) clutch. It didn't feel like it was slipping, I a 1990 Plymouth Laser Turbo that the clutch went out on, so I know what slipping feels like. This was more like the engine was "lugging" because the trans was in too high of a gear for the speed & RPMs

I do too, but I am convinced our clutches don't slip like old ones did. My first clutch I drove over 60k miles and it took the 2nd, 3rd and 4th synchros with it eventually. My twin disc is already acting up and its just over 30k miles. Neither ever slipped, especially not the twin disc, but my stock clutch was trashed when I finally changed it.

Kinda feels like when you start moving with too little gas and the engine bogs and then it kinda feels like the clutch is bouncing on the flywheel, except at speeds of like 40mph or so, right? I've seen guys on the forum (a ZL1 thread comes to mind specifically) where the OP is like "yeah, I'm sure it's not my clutch because of x reason" and the other guys said to post a certain file out of the datalogging software and you can see all these microstutters during a dyno pull where the clutch isn't grabbing properly.

(found it, post #5, guess my memory about the conversation was a tad off, but still) http://www.camaro5.com/forums/showth...ghlight=clutch