need help, having fuel cut or tune issues

[dmjensen]

let see if someone knows what's wrong with this, i have a miller setup (chip and maf with turbo base tune) sometimes while driving but not all the time the car will jerk under slight acceration a/f says its around 17-19. thats lean so its fuel something. but it only does it once in awhile, or under boost it will cut out and sound like its backfiring with high numbers on a/f.
it seems like it tends to do it more often at higher speeds (generally 5th-4th gear going 45-60mph)
as far as i know the fuel pump, filter, and regulator haven't been replaced.
has anyone had this problem and have a solution?

[dmjensen]

Anyone? I'm going to end up just replacing parts untill the problem is solved so someone help me out so i dont have to spend moneyz on things i dont need to

[LowR3V'in]

It's tough to say without a datalog. Everything is just going to be a wild guess.

I guess that if you're using a different setup then what miller used for the base tune then
your leaness might be "normal" and needs to be tuned.

Or fuel pump relay is losing contact from corrosion once in a while.
Just some wild guesses.

[dmjensen]

I have 30lb injectors, and a 10.45psi wastegate spring to if anything i should be just a tad lean but not as bad as im seeing

[einstein57]

Mine does that when its cold

[Jaxx_]

My money is on a misfire. take a look at your plugs and see how they look. gap them down and see if it improves. if you're at like .028 take them down to .024 or so, all the way down to .020 if you see a slight improvement.


unburned fuel will register as lean.

[dmjensen]

Mine does that when its cold

Thats when i notice it happens the most, ill check my spark plug gaps when i get the motor back in the car sometime next week

[einstein57]

I was told the maf was bad. Have not swapped it to confirm.

[mattdk318i]

im having the same issue with my miller dohc turbo tuning kit. Ive moved my 02 sensor per brodys suggestion. Replaced fuel pump with new walbro 255. Replaced all fuel lines and fuel filter. Replaced the fuel pump relay and even wiring to the fuel pump. Thinking there was a amperage issue.
Problem still there. Ive tried richening up the areas where im running lean and the issue still exists.

But its doing axactly as you describe.

[dmjensen]

does yours cut out and almost miss fire at WOT?

also check your fuel pres regulator