i have a b20 in my 90 teg. i have a question about the idol it revs high then it drops and then revs high again, it just keeps doin that until i put it out of park. i was wondering if anyone would kno the reason why it does this and how to fix it.

 

Idle. An idol is something you worship. There are a few things that can make cars idle strange like that, usually it's a sensor problem, or a clogged bypass screen on your idle air control valve (IACV). Do a search, there are many many threads on this topic..

 

Check your intake manifold there might be a leak, spray some break cleaner around it to check for leaks

 

You also can use carb cleaner and if your idle drops a little you found your leak. You can also spray the shit out of your IACV with the carb cleaner to clean the screen and inside of it.

 

Also check timing and vaccuum lines.