Tried replacing my IAC, and my starting problems are now noticeably worse, which is... interesting. Now the car will stall out completely without throttle input upon startup. Any idea what this could mean?
Interesting, I didn't know about that. Guess it wouldn't be too hard to take a look, although my car is a 1993 so you would figure that Ford would have fixed issues like that by then.It can cause all kinds of weird problems.
I will try this as well.With the engine running, Unplug the IAC. Does the engine stall?
If so, the throttle blade is too far closed. Need to open the set screw a bit and perform an idle relearn procedure. Sometimes when the IAC is being called on to 100% manage idle due to the blade being closed too much) you get a surge on startup. The car should be able to idle somewhat (although at a low rpm) on it's own with the IAC unplugged.
The thing that is really throwing me for a loop is that the car behaves so well once it's done having it's little hissy fit upon start up. I feel like that would rule out something like a vacuum leak or fuel pressure problems. I will look anyway though. I also doubt that air flow to the MAF could be disturbed since it has a stock airbox and stock intake tubing.Vacuum leak
Low fuel pressure
air flow disturbed going through MAF
mis matched MAF/injectors
improper reset procedure
wrong/mismatched/worn parts
wiring issues
ignition switch
I have a factory A9L and factory tune, it even still has the little "do not remove or it will void your warranty" sticker over the opening.I'm not sure if this has been asked yet. I did a quick browse of the comments. Do you have a stock computer with a 4 bank chip?