My 88 CRX DX has some major idle issue. Sometimes it is not bad but 80% of the time it is awful. Sometimes I will start it and it will rev up to 3500-4500 by itself and ill have to pull back the accelerator to get it to stop or slow down. If its in gear and I shift sometimes it will continually rise in rmps and then go back down when its in the higher gear. Sometimes it will also rise by itself if I take it out of gear to neutral. Say im in 1st and it at 2500, ill pop it in neutral and it will contiune to rise until 4000+. If its in 1st or 2nd and its rising by itself it will accelerate the car by its self or just stay at 2500-3500 while going ~30 in 3rd gear. I dont think this is normal and is probably why I can not get more than 29 to the gallon. I have replaced plugs, wires, cap, rotor, air filter, valve cover gasket, and sprayed the throttle. Its driving me insane. It either revs high as hell or idles at like 250 and like sputters like about to stall out. and sometimes when i pull back on the gas pedal it will rev so low it will kill itself. What the hell. Please help!

 

Check for vacuum leaks and report back.

 

Checked and there were no vacuum leaks. Now what?

 

I think i figured it out. I looked around and this part looks like it is missing something. Think this is the culprit?

 

That spring in the middle has an arm with a hole on the end of it. Its almost inside that circle like cone. It moves freely. It looks like it should have something attachedto it going into that metal thing.

 

I believe that is the dash pot for the tandem valve.
that would mess with idle.

 

Does throttle body return correctly? If you have to pull the pedal back to return it, sounds like the line is jamming.

Wont fix your low idle, but it sounds like you might have a few problems. That's the worlds smallest picture, and it's hard to see if anything is missing.