ok so i searched the forum with little luck, but heres my problem when doing like 30 mph if i hit the gas at about 4000 rpm and 8 psi boost it starts sputtering and goes way lean and if im on the high way doing like 65-70 and give it gas it goes up to about 3000 rpm and only like 3psi boost and does the same thing so i know it happens more depending on load so it has to be fuel/tune related im guessing, any sugestions will help.

what ive done..custom turbo setup, 8 psi boost, intank fuel pump, and 42lb injectors, nelson did the tune and picked injectors and pump and every thing ran great then i went t.d.y. truck didnt run the whole time, got back 20 days later and found bad battery, so truck might of been with out power the whole time. could this of caused problems??

 

Do you have a Wideband O2 and do you have a why to log your tune? What is the Wideband say if you have one? My bet is that it is running lean or your getting alot of KR. This would cause the engine to pull timing and run like crap.

 

no i dont have a wideband o2 and i dont have any way to log the tune going to buy hp tuner on friday and a wide band o2 also so i have a few things left to get but i do have some friends at the dealership so ill see if they can view my KR, im running 93 octane new plugs and wires and knock sensors. what else can i check that would cause KR?

 

what did you gap your plugs at?

 

because of the bad battery....I would double check alternator output, power, and grounding terminations and also question same tank or source of gas with issue....and look at the other easy stuff....spark plug wires seated not broken etc. at least until you get access to a diagnostics tool (i.e. hpt on Friday). good luck.

 

Is it sputtering, or would a better description be chugging, like the sensation you get under certain circumstances when you are pulling a trailer?
If it is chugging, that is an indicator of leanness.

 

if its popping then check the gap on the plugs, other than that check for kr, or lean pop. Other than that it could be a spark issue. I kept blowing out the spark and swapped to a tr6 gapped to 32 and solved that problem.

 

I'm gonna say check your spark plugs. What kind are you running, and how old are they?

 

The key is it was running fine, the pcm doesn't change.
Tape a fuel pressure gauge on the window and go for a drive, see what it's doing.

Chugging, hesitating, etc, could be a miss, so check for cracked plugs, or bad wires.
I doubt an injector got plugged up.

My truck had a popping / chugging sound under boost when a valve went bad.

 

could be way rich as well. If he doesnt have a way to monitor the AFR who knows which it is doing lean/rich. When I first started tuning my truck (within first hour) My wideband would go down into the 9's when first creeping into boost and it would sputter. Just an idea.