408 LQ4 problems

[pl4yboy]

Thanks for the quick responce, I unplugged the MAF, at first it didn't want to idle, after a few restarts it I let it idle, one thing it did fix was the hesitation when I stabbed the gas for a sec, it went away, I then turned it back off, plugged in the MAF, and the hesitation was back. Do you also think that the stock MAF is a big restriction with all the mods I have listed?

The stock MAF is fine. It's probably either dirty or bad. See if you can get another one to try out of a different truck. Also, try cleaning that one carefully.

[mr2cam]

The stock MAF is fine. It's probably either dirty or bad. See if you can get another one to try out of a different truck. Also, try cleaning that one carefully.

Ok, we will clean it first and see how that works, thanks for the help guys, I will report back, and if anyone else has suggestions let me know, thanks a bunch!

[mr2cam]

One weird thing is though it never did this with the 5.3, and it's the same MAF from the 5.3. But the MAF did sit around for quite a bit before we got the motor in the truck so it could be quite dirty, guess we will find out tomorrow.

[farmtruc]

Since the hesitation went away when pulling disabling the maf, might be a dirty maf or the PCM thinks there is a lean condition or there is one.
A map sensor doesn't respond the same way to a vac leak.

What are the ltrims showing when the ma is plugged in?

[mr2cam]

Since the hesitation went away when pulling disabling the maf, might be a dirty maf or the PCM thinks there is a lean condition or there is one.
A map sensor doesn't respond the same way to a vac leak.

What are the ltrims showing when the ma is plugged in?

You mean the fuel trims? This morning before we did any revisions with the base tune it was showing good, I think one bank was 0 and the other was -3 on the Verus. Also when I sent Vince the first data log he thought the fuel trims looked good, but the truck does act like it is running lean.

[mr2cam]

I should also say that once the truck is driving it is smooth as silk, drives very nice..

[farmtruc]

There are so many things that could be going on.
Good ltrims indicate there is no leak and the o2's are working.
The fact that the engine runs with the maf disconnected means the map is working, actually since the trucks starts at all means the map is working.
Good ltrims also means the fuel pressure is ok, as long as the ltrims are around 0 during idle and normal driving (loaded).
o2's good, map good, no leaks good, fuel pressure good, only thing is the maf, be sure you swap it out just to make sure it's not that. I've seen weird things happen due to a maf.