sputterin

[rolin17]

hey anybody help me out. I have 2000 f350 7.3, when I first started up for
it doent matter when just when I start it up, It spits and sputters like it losing fuel,and the check engine light comes on had it scaned and nothing came up but when it warms up it runs fine.Also this just started after i straight pipe the exuast.

[mlitkenhus]

i have an 01 f550 that is similar. it spits and sputters until warmed up then runs good. would be interested in any response you get. i am looking for a similar fix.

[DiamonD 550]

ok if it were a gm i would say coolant temp sensor, its not telling the computer that it cold and it thinks its warm so it uses less fuel. just a guess

[ajpu1983]

I'd find somebody with a decent scanner and pull memory codes as well as run an injector buzz test and cylinder contribution test. Also you can put a 5k ohm resistor in the oil temp sensor to trick the PCM into thinking the truck is warmed up so you can run the cylinder contribution test cold when the engine is acting up. Also read ICP and IPR when it is skipping/acting up to see if either ICP (psi) or IPR duty cycle (%) are really erratic. I would hunt that check engine code before anything.