I know that in EFIlive messing with the steps on the IAC I could get it to idle down and stumble, so thats all I really have right now. If that is possibly getting stuck at times?

02 sensors looked good, they were reading the same. Injector rates looked good. If it was something that was wasnt completely random, I would think vacuum leak, but again last night it ran great all night, and this morning at -10F it started fine and ran fine to work.

 

Did you delete the EGR? I didn't have my plug sealed, and thought it being pressed in enough was fine, but I had a vacuum leak and it would do the exact same thing. Took it out and put some rtv silicon around it and had my tuner mess with it some more and it fixed my problem.

 

I swapped intakes a while ago to a 03+ and there is no provision for the EGR on this one.

If it was a vacuum leak, it would happen every time i would think. This doesnt matter, hot, cold, etc. Its always after a start up. Either it starts and its fine until I shut it off, or it runs like crap until I shut it off. The next start up is a crap shoot as to how it will run.

 

I had an issue with my engine coolant sensor. Loose connection would throw the readings off and it wouldnt start sometimes when warm. It would run super rich then fix it self. A scan tool will show the temp sensor readings and you can tell if thats the issue. It would -60 to 77 degrees back and forth.

 

thought about that, but everything checked out. ETC sensor was right on. Nothing sensor wise (besides one possible oddity with the IAC sensor) was off between a good idle and bad idle scan. So far today its been fine again.

 

Good point on the vacuum leak happening all the time! I broke my tab that holds the temp sensor on the driver head, and sometimes it would back off. I would drive like total crap, shift wrong, and when it lost total connection it killed the motor on the highway going 70mph

 

Check and see if your temperature gauge sensor good(driver side head)

 

everything checked out on that. My gauge and ECT in datalogging showed proper temp on bad idle as well as good idle.

 

One more thing, I had a MAP sensor that has loose in the intake and would cause issues as well. It would be fine sometimes then other times it would leak due to a broken tab.

 

Next time take note of the engine temp. I think it has todo with your desired sairflow table being off at lower ect temps.