So, My 91 N/A has a check engine light on that's been on for about 4 months...
The car runs perfectly fine aside from 2 things,
1. When in gear, and the engine is running from 1.1k-2.5k there is a ticking that sounds like an injector coming from the engine bay and is very noticeable from the inside of the car... oddly enough it doesn't speed up with the revs, just stays the same tempo... tick tick tick tick tick
2. *sometimes*, very occasionally the idle will drop to about 600 and run rough, as soon as I put on throttle it runs fine, but if I let it drop to idle, the idle stays at 600. after about 30 seconds to 1 minute the idle kicks back up to 900-1000 and runs fine.
I don't see/hear any vacuum leaks, and the previous owner (good friend of mine) says the check engine light is coming from the Cam Angle Sensor (also apparently it's the ICM, yet the part is listed online as a Cam Angle Sensor). Still doesn't explain that tick though...