So this has me scratching my head, the car revs up just fine, only issue is idle sounds rough and spark is weak. Constant check engine light as well, comes up as code 33. My mechanic said the distributor might be bad, is that a possibility? Just looking for second opinions since it's such an odd issue

 

https://www.freeautomechanic.com/gm-...af-sensor.html

All things are possible, correctly diagnosing the issue is when a real mechanic comes in and not just a guy that can guess and change parts.

 

Not sure if you got your issue resolved but if you have some basic diagnostic tools you should be able to pin point the cause yourself. Some mechanics are afraid to dive into a problem to correctly diagnose it and will result in something techs refer to as shotgun diagnosis or throwing parts at it and hoping it fixes the issue. If you have a vacuum gauge you can hook it up to manifold vacuum to see if it’s within spec for your engine, if it is then you’d need a vacuum hand pump and a multimeter with some back probes to see if your MAP is registering changes in vacuum. Hope this helps, as always it’s fairly difficult to diagnose a problem without doing the tests or seeing the vehicle myself.

Also, a somewhat quick check without any tools that will tell you if the issue is your MAP would be to unplug its electrical connector and then attempt to run the car. The ECM should sub a default value for manifold vacuum if functioning properly. If running improves that lets you know that either the sensor itself or the associated wiring is going to be the cause of your problem. Again a proper diagnosis is usually the only way to find the root of your problem.