I have a 96 honda accord with a 94 h22 and my car idle between 1500- 3000rpm s up and down no matter if cold or warm. I disconnected the iacv and the idle went down 1200-1500rpm stills goes up and down between these rpms, So what could be the problem.

 

open up the iacv and clean it, play with the idle screw, check if the map/tps sensor have the corresponding plugs.

 

Possible vacuum leak IMO, the IACV is working and trying to control idle, but it is out of its range. I had a similar problem with a h22 swap and a leaking air bypass valve on the manifold. Prelude ECU or what engine management are you using?

 

Im currently running a automatic p13 ecu but waiting for my manual p13 ecu could this be the problem

 

I believe it could if it has not been chipped, but I am not overly familiar with the specifics of the auto ECU in a M/T vehicle.

 

So I should just wait for my ecu, whats the difference between any auto and manual ecu

 

I had this problem on my Prelude. If TPS is good then it could b ur fast idle valve under the TB. It cost me 100