Normal Fuel Pressure

[Dandy97]

Originally Posted by bradslt5

what is your problem?

A long time ago I think I was in a few fights that started with that question.

I have been fighting (pun intended) with a very bad stumble when the car is cold for awhile. It idles fine but if I try to drive it before it goes closed loop it's like it's running on 3 cylinders up until about 2500 rpm's then it kicks in. If I start the car and let it idle for about 15 minutes and get up to operating temperature, it runs fine. It doesn't throw any codes when it runs bad.

I have run through the diagnostic charts in the FSM that relate to this problem and have not found anything wrong.

Two weekends ago I replaced all of the primary fuel injectors because I had three bad ones, one measured 9 ohms at the coil and the other two measured about 6.5 ohms. Needless to say they were not working very well. I also replaced the coils as long as I had the plenum off again. Also in the last 1000 miles the following has been replaced for one reason or another:
secondary fuel injectors
secondary vacuum pump
plugs (about 250 miles on them)
plug wires
pcv's and top & bottom hoses
iac
map sensor
fuel filter
replaced an unknown custom prom with a marc h. prom

None of replacements effected this primary problem, they all fixed other problems of course. The stumble problem when cold has been uneffected and has gotten continually worse over the last year.

I have pretty much run out of ideas. Whatever it is, I think it must be an electrical device because it starts working better when reaching operating temperature. One thing I have thought about is the ecm, maybe the fuel injector drivers are shot from driving bad fuel injectors. I am probably going to try swapping out the ecm this weekend and see what that does. So we shall see. I really want to get this solved as I originally purchased the car to be my daily driver in the summer.