V6 MPG

[KillerBomb24]

Originally Posted by ElderJ

18 seems rather low on a V6, unless you're driving it hard. I'm getting 22.5 on my LFX auto, and I can't stay under 100 on the highways (although I crawl like a turtle in the "city").
I use Kroger 93 octane.

My guess is that I idle it to much. Whenever I cold start it I let it sit for like 3 minutes so that’s probably what eats up a good bit of gas.

[EMB135Driver]

You’re getting worse mileage than my SS….I reset the DIC at every fill up, and it’s always around 19.6-20.2 at the next fill up. I verify it by dividing the miles I drove by the gas used and it’s pretty close.

[Tony-8]

I had a 2014 2LT RS LFX and consistently got 23.5MPG overall and I always used 93 octane. I get between 20 and 22 overall in my SS, depending on how and where I drive.

[AlanRubin]

Originally Posted by KillerBomb24

My guess is that I idle it to much. Whenever I cold start it I let it sit for like 3 minutes so that’s probably what eats up a good bit of gas.

No, idling in gear for long periods of time really rips into average MPG. I was
at 24.6 once, did a run, and sat in accident detour traffic for 45 minutes,
inching away, and it dropped to 18 something average...

Idling out of gear does not count towards MPG calculations, and neither
does coasting. Once you coast steadily for more the 5 seconds, the
injectors are shut down. I watched it on a scan tool, they all dropped
to 0ms. I can also hear mine, I took all the insulation off. There is a
foam cover over the valley where the injectors are, and behind the intake
manifold, all to quiet down engine noise. I can hear them shut down when
coasting.


I am still at 25.5 average. 380+ miles a day...

[granatl]

My 2018 v6 w/ AFM currently shows 28.8 MPG for 450 miles. That's slightly above the EPA registered 28 MPG on the highway.

[ElderJ]

Originally Posted by KillerBomb24

My guess is that I idle it to much. Whenever I cold start it I let it sit for like 3 minutes so that’s probably what eats up a good bit of gas.

A couple minutes of idle at each start shouldn't impact your mileage efficiency any, if at all. You more than likely have other issues at play, here (bad gas, bad sensors, dirty injectors or plugs, fuel pump issues, etc etc...). I'm not a mechanic, so I am of little use to you at this point other than benchmark purposes.

[ChibiBlackSheep]

Pull your plugs and see how they look. Make sure they aren't completely blacking out and showing that you are running rich.


If you do pull plugs and see them looking very rich, I would start diagnosing. I noticed this before I had HPFP issues.

[KillerBomb24]

I scanned my ECU at Autozone and they told me to change my fuel pump, she said I am running lean. Pretty sure I found my issue but I will update you guys if it changed anything.

[ChibiBlackSheep]

Originally Posted by KillerBomb24

I scanned my ECU at Autozone and they told me to change my fuel pump, she said I am running lean. Pretty sure I found my issue but I will update you guys if it changed anything.

Your car has 2 fuel pumps. One that pumps the fuel to the engine and another in the engine that pressurizes the fuel for the direct injection. I had a similar issue where my high pressure pump went bad and was leaking fuel out. Definitely get into a shop to get them tested.

[KillerBomb24]

Originally Posted by ChibiBlackSheep

Your car has 2 fuel pumps. One that pumps the fuel to the engine and another in the engine that pressurizes the fuel for the direct injection. I had a similar issue where my high pressure pump went bad and was leaking fuel out. Definitely get into a shop to get them tested.

Its the high pressure pump. I can try to replace it shouldn't be to hard.

[ChibiBlackSheep]

Originally Posted by KillerBomb24

Its the high pressure pump. I can try to replace it shouldn't be to hard.

Make sure you also replace your plugs and the feed pipe (believe it's listed as a 1-time use item).

Also make sure you look at your intake, make sure it doesn't have any excessive buildup

[Ruger2506]

My 2012 was averaging mid 20's (24-26 mpg). Then I added bolt on mods, an E85 tune and started running E85 pump gas. My average mileage is now low teens (13-14 mpg). Of course that's my fault, not the car. After the mods and change in type of fuel, the car may hardly ever be running below 3000 RPMs and may frequently hit 6500-7000.

[KillerBomb24]

Originally Posted by ChibiBlackSheep

Make sure you also replace your plugs and the feed pipe (believe it's listed as a 1-time use item).

Also make sure you look at your intake, make sure it doesn't have any excessive buildup

Do you know any good videos showing how to replace the high pressure fuel pump from the LFX engine?

[ChibiBlackSheep]

Originally Posted by KillerBomb24

Do you know any good videos showing how to replace the high pressure fuel pump from the LFX engine?

I had a good step-by-step bookmarked but it looks like that domain is no longer around. It was an old write-up on bowtie v6 dot com. I know there was a lot of drama around that website and those owners, so not surprising that it's gone. (can't even write out the domain without it turning to asterisks)

You'll just have to check and look around. I personally looked at the step-by-step and deemed my comfort level not high enough to perform the job in my garage at home. I didn't want to mess with these high pressure systems, and I believe I needed a specific tool to align the new pump with the cams, so I paid a local shop.

Fixed up that car, got it running right, returned it back to stock and sold it. Took a chance with the new v6 engines, thought they had some good potential but it wasn't worth the headache. I wanted to go back to the dinosaur tech that this v8 is based on haha