I have a 93' integra GS. The car is stumbling and shaking bad at idle. It sounds like it has a miss in it. But when you hold the revs the stumble goes away at about 3K and then is smooth. I would think if there was a miss it would just get worse with RPM's. but after that 3K it runs and sounds fine. Also at idle if you put your hand over the exhaust tip it is not a smooth exit. It exhaust gasses feel like it lopes like its got a big cam in it.(sorry hard to explain, its like blup..blup...blup) What's goin on with this thing.

 

sounds like tune up time to me, check and replace if necessary spark plugs, spark plug wires, cap and rotor, fuel filter, air filter, see if the problem persists if it does do a compression check and see if one of the cylinder's compression rates are off from the other 3 could be uve got a vacume leak or blown gasket somewhere. but always start with the basics first and work ur way to the more complicated problems could just be crappy spark plugs or bad gas. and what are u idling at?

 

its idling at about 500-600

 

you could always try the dollar bill method and see if you have a burned valve.... hold a dollar bill in front of the exhaust and if it sucks back into the pipe, you have a bad valve