engine runs like crap when cold

[mr heavy-chevy]

Mine was also new. It got plugged in about three months. I had crap in the tank.

i think you may be right.... i just pulled it and black gas came out of it....

i poured this into the box the NEW filter came in... lol
thats really bad.....
guess i will be going through filters much more frequently.... bummer.

 

[mr heavy-chevy]

DID NOT WORK

engine still stumbles when cold.... but warms up and "fixes itself" a little faster now.

back to square 1

 

[Georgeb]

Still would be good to know the fuel pressure.
Could be a weak pump, sucking air in the tank, some of that crap made it up to the injectors or a bad fuel pressure regulator.
Also just for giggles whats the ignition timing set at?

 

[mr heavy-chevy]

it has new fuel pumps, so i doubt its fuel pressure.

i think it may be the idle air control valve..... because the problem is getting worse. it happens warm now too.... but some B12 seems to have solved it.

still no check engine lights.

 

[mr heavy-chevy]

fixed it.

it was a loose & varnished up idle/air control valve lol

would not throw any check engine lights. finally checked it while doing a thorough throttle body spray cleaning

 

[Steven]

I would disagree with the fuel filter, when mine clogged it was about 60 and it would not sustain itself at all. Even in idle it was really rough. Lots of missing too even after it was hot. Try to run it on starter fluid. That will tell you if it's spark or fuel problem. Done that to my truck many of times. It's a quick easy check and will help narrow it down