So here it is:
85 GT -
I leave the battery unplugged while the car is stored. Plug the battery back up, start the car, it runs rough (Idle jumps) and gives a code 33 (MAP Sensor). Odd because I just replaced the MAP - must mean the MAP cable under the plenum is cracked.

Now here's the strange part - after the first time I start the engine after plugging the battery in, the car refuses to start without giving gas, and will not idle at all (Will die if I let go of the gas). This happens regardless if the engine is cold or hot.

I then unplug the battery, let the car sit for a few hours, plug the battery in again, and it starts up, idles rough (Without me giving it gas). Turn it off, won't start again.

I don't have time time right now to pull the plenum, but I will hopefully get to it next week - I was wondering if anyone has any idea what's up with this strange behaviour?

Any time that you unplug the battery, you also reset the ECM.
Any time that you reset the ECM, it must relearn the idle properties of the car. The car must be driven over 35 MPH for a short time after it has warmed up. My Fiero will idle awlfull after a reset for a while.
I dont know about the gas difficulties.
There is a chance that by unplugging the battery often that perhaps the cable has weakened or the reattatchment is not secure.

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jetman
Silver 86 SE 2M6 4-speed, with "check wallet light"