O.K., I recently spent all my time and $ swapping a F22A1 for a F22A in my 93 lude S (the other engine was blown and I have no $ for a bigger engine), yesterday I finished the engine rebuild and started the car for the first time in months, I knew that not everything would work on the first try. For some reason the engine rev's up and down constantly while in park. It will rev up to about 1800 and then back to around 1100 and so on. All vacuum lines are connected and I even tried disconnecting some to track the problem. All I could figure is I replaced the old injectors with new Accel HI flow injectors (could be a problem with the flow and the ECU) or maybe a bad fuel pressure regulator. If any of you have ever had this problem or know how I go about fixin ity I would deply appreciate it. I have been working on this car for months and can't stand it anymore, the wait that is, and would love nothing more than to drive.

 

somebody, anybody. I really need help, honda experts @ local shop won't tell secrets without $.

 

I had the same problem for a little while.

Start simple. Make sure your engine has plenty of coolant in it.

 

and bleed the cooling system, do a visual inspection

 

In top of the throtte body there's a screw, that could cure it. Mess with that screw first, it might fix your problem. If that doesn't work than is your intake air control valve. Is in front of the intake manifold, i took mine out, and i cleaned it w/carb cleaner and fixed my idle problem. But first mess with the screw, use a flat head screwdriver.

 

if not ^ then might wanna check tps, back of the throttle body...

 

my friend has the same problem in his CR-X ( i know its not a prelude) but he was told its the IAC (idle air control) valve

 

I will check all of these and let you all know what happens.

 

coolant was topped off and distributor moved to correct timing fixed the problem just fine. Thanks everyone.