Hey guys! My name's Mac and I am on my third Honda, but first project car. I've got a '93 Prelude with an H23a1 (original motor) in it. I've searched til I'm blue in the face and still haven't found an answer....So here goes:

Recently, the engine idle is off. It started off revving up and down on its own from 1k -2k RPM. I cleaned the fitv and the iacv, checked for vacuum leaks, etc. no leaks and the idle smoothed out for a couple days. Now it is doing the same, only the rpm range is different. It surges quickly between 1k - 1.2k rpm. I've been told that the timing is off by a couple friends that tinker on their own cars, but it smooths out once I give it a little gas. Another symptom is that I have to give about 1/2" of pedal before it smooths out. This causes erratic, jumpy movement of the at when it's in motion and I'm not giving it alot of gas that makes it look like I can't drive a manual. (Sorry, I don't know any other way to describe it and no, there is no slack in the accelerator cable, already checked that out too.)

Any ideas/help is GREATLY appreciated!!

 

welcome to the site. check to make sure your tb is clean inside ie the weep holes. also check to see if your throttle cable isnt stretch or has come loose. that can be the pedal issue. Easy is disconnect intake and have someone press on the pedal slowly. check to see if at the same time the pedal is be pressed the throttle plate is opening.

 

Thanks for the response. The idle has smoothed out, but now I'm back to the surging between 1k -2k. Aye aye aye. Idk.
It's not the accelerator cable or a vacuum leak. Already rules those two out. Also cleaned the Fitv and iacv. Argh.

 

The surging is most often air in the coolant system screwing with the fitv and iac valves. Did you follow the fitv cleaning procedures on this site? Do a quick bleed of your system using the bleeder screw on the tstat housing.