hi, i'm new here and i just bought this 91 accord cause it was cheap and becuase my truck kicked the bucket. the one thing that is wrong with it is the rpms, when i'm stopped, will idle around 1,000 or right beneath it and drop to around 500. it'll keep doing that going up and down, up and down. btw, it's a 5 speed manual. any suggestions on what to look at and how to fix it would be greatly appreciated, thanks!

Could be a few things.

1) a significant air leak somewhere on your intake manifold or where it meets the head.

2)Either replace or clean the idle air control valve (iac, iacv, or iac servo). Its on the front of the intake manifold. Sometimes cleaning them will improve the problem, but not fully correct it until they are replaced. YOu can usually find them at a junkyard or on ebay for under $50.

3) It is possible you just need to clean the EGR valve, all 3 are potential problems, but I'd personally first guess #2.