Im using 93 octane gas - always the premium gas at whichever station I go to. I tried checking the MAP and IAT wiring was connected properly, and then I disconnected the MAP sensor and started the car for a laugh. The CEL of course came on, and I noticed there was a slight stumble and gentle stuttering when I went to about 50-75% throttle from idle as it climbed through 2k rpm - it was sorta reminiscent of the way the engine would react when the stuttering was happening, except it was much less noticeable and let the engine keep revving. Im thinking that even if it is a MAP sensor going bad, that may not be the cause? It seems like the ecu can bandaid the loss of MAP sensor reading, whereas it could not bandaid whatever was happening to the car, especially on that morning. Im thinkin the MAP sensor might not be the issue. The other crazy thing is that I havent had any CEL's through any of it. I was looking through the Helms manual for the car and on pg 11-84 it lists a symptom chart for troubleshooting symptoms which will not cause the CEL to come on. Among the listed symptoms are "Misfire or Rough Running." I looked into the sections it mentioned, and it refers to the PGM-FI System section on Random Misfire. In the symptoms and causes chart, it says that for a misfire which occurs at a non-specific time (could be accel, low rpm, high rpm, etc...) check the following in the following order:
1) Fuel pressure
2) Distributor and Ignition Wires (already replaced)
3) MAP Sensor
4) ICM (Ignitor)
5) Valve Clearance and Crankshaft Position Sensor
Im inclined to rule out #1 since if there was a FP problem, it would be more persistent, and easier to replicate. #2 is ruled out since Ive already replaced them. I dont know if the MAP sensor could even cause this, since it seems like the worst it could do is run a bit rough, and even then it should thrown a CEL. #4 I guess is a possibility, and since they dont come too cheap, I havent replaced it yet. As far as Valve Clearance, I havent had the valves adjusted ever, but I will probably get that done along with the timing belt in a few weeks time.
Basically this doesnt seem to help alot - according to the book I should check out the ICM, but does anyone else have any ideas, thoughts, or experiences with anything like this?
Thanks again guys!