Ive been having cold startup problems lately where when I start the car I have no vaccuum pressure whatso ever and the car sounds like its missing really bad or like its only firing 2 cylinders, but its not its just stumbling to stay going. after about 5 minutes of the vaccuum slowly rising as the car warms up it will run perfect.

I have an safc with settings on 6 in/out.
I just replaced the o2 sensor which seemed to fix the problem for about 3 days and now its back.

I just replaced the pcv valve as the old one wasnt working at all anymore (I could suck through both ends with no restriction.

Im getting a CEL for insufficient EGR flow (Im not blocked off)

Im hoping its nothing internal (I would think an internal engine problem would not get better with warmer temps.)

Im thinking maybe my map sensor is starting to go?????
I might try to warm the map sensor with a hairdryer prior to a cold weather start to see if it helps..


Any Ideas??????

>Im getting a CEL for insufficient EGR flow (Im not blocked
>off)

it's probably the ECU testing the EGR thats causing your problem. It shuts the idle air valve and opens the EGR. if it gets enough air to idle the way it thinks it should, you're fine. if it doesn't, it bucks and stutters and then fires off that code. Doesn't do it all the time though, and shouldn't check on every cold start - i don't think it checks on cold starts at all. i beleive it waits for a running temp condition before attempting that test.

Could be a dirty idle air valve, coupled with a dirty EGR assembly.

Try removing and cleaning the egr valve assembly, and shooting some carb cleaner or B12 though the idle air passage.