I just did a complete tune up on my 94 Accord (non VTEC). I put in a new timing belt and balance belt, plugs, wires, hoses, coolant, the works. I also cleaned the throttle body with carb cleaner...

I fired it up once it was all together and things seemed to be ok, until about a minute of idling, it started surging between 1200 and 1700 rpms, alternating continuously. I double checked all my connectors, vaccuum hoses, and wires, etc, but did not find anything to explain this.

I took the car for a ride to see if it would settle itself, and the problem seems to go away when the car is in drive or in reverse, so it only surges in park and neutral.

I did some searching and some people said it could be the fast idle thermo valve... so i took off my throttle body and looked at the FITV, and it seemed ok tooo, nothing out of the ordinary. it seems to be just a plunger type valve, so what would cause it to do this in only park and neutral but not drive or reverse?

What else could i check out? Should i try resetting the computer? Why would this problem happen after the tune up?

Thanks!