Guys,
I've been following this thread because my VX had this same idle bounce problem, and my current '95 DX has a little bounce once in awhile as well. Here's what I read on a honda-tech.com thread aboutthis problem:
"It's unlikely its the Idle Air....that's the f*ckin annoying H-T answer to all idle problems that is rarely the actual issue. What is FAR more commonly the issue is the thermo valve below the throttle body. The valve seat inside screws it's way out and the valve never seats when the motor reaches operating temp allowing constant blow by air...essentially a vacuum leak.
Pull off your intake tube and idle the motor to operating temp. On the inside of the bore of the throttle body there are two holes in the side. With the motor at operating temp put your finger over the lower hole. If it's sucking vacuum at operating temp, that's a problem. You need to take the assembly apart beneath the throttle body, screw the plastic valve seat all the way in, then back it out 2.5 turns. You don't want the valve seated when cold, but as the coolant warms the thermo valve you want it to seat and shut off the bypass air.
That's likely your issue. Check that first, then if that isn't it check the idle air. The Idle Air gets blamed on this site constantly for bad idle just simply because the work "idle" is part of its name I swear. I've done this for years and I've fixed the bouncing idle syndrome more times than I can remember and out of all the times the IAC was bad twice, maybe three times. When they are bad the rubber boot inside is usually cracked or broken down. The IAC's are pretty straightforward to check. Get a two pin plug as a test plug and run some extension wires. Hit the IAC with 12v....if it clicks it's good. It's a simple solenoid...that's why they rarely go bad."
http://honda-tech.com/zerothread?id=...ostid=30429468
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