86 Cutlass Ciera 2.5 TBI Code 42,35

First the car had trouble starting and it would stall at any rpm, so I took the car into my auto class and put it on the computer. It gave me error 42 EST (Electronic Spark Timing Error) then error 35 Idle Air. We fiddled around with it at school, and nothing. So I adjusted the timing and changed the spark plugs(they were cracked anyway). After that, the car doesn't stall at higher rpm, only when I start it on an incline and shift to drive(sometimes). It will also be slugish when driving(on occasion). The filter also became very black through the duration of this problem.(The filter is no more than two months old) I checked the fuel filter and it was clean. The fuel injector is throttle body injected, so you can see it, and it is spraying fine. I tested the resistance of the plug wires, and they are ok. What else can it be?

Thank You

Also, where is the air temperature sensor on this car, if it has one?

Mine had similiar problems, mostly ran poor and would die when put into drive, turned out to be the distributor, which is where the computer gets the engine rpm signal...the pickup, module and pole piece(reluctor) are non-replaceable so it's a new distributor...2nd one in 2 years no less. I read about a bad coil messing up good distrubutors so I replaced it too. Runs great now.