I did an engine swap (h23a1)in my 92 si back in march. the engine came out of a 95 prelude si. everything was running fine until like 2 weeks ago. it started surging between 1100 and 2000 fairly slowly. if i put the car in gear 1-5 and let the car idle down to 1100 itll give it gas, without my foot on the accelerator, up to 1500rpm and then die off to 1100rpm and back up. i bought a tps and changed it because i ohmed out the one on it and it was bad. the engine only has 62000 miles on it. the car drives beautifuly but the damn idle is pissing me off. its not the egr, or tps... and the IAC doesnt work after the car warms up so what could it be? i heard something about having to adjust these valves periododically. i dont know much about honda.. im learning. i know a good deal about dodge though.

 

i heard a pcv or somethign can fix that
make sure you got no tears or rips in vacumm hoses:

what bout fuel pump< is that ok?

 

sounds like you might have a vaccuum leak. could any of the hoses on the intake manifold been mixed up?
you can take carb cleaner and spray it all over the hoses when the idle is surging. if the idle smooths out, then you have found the leak. just repair or replace.

 

I know someone who had a similar problem. They changed the plugs, plug wires, and fuel filter as a start. If that does not work try the pcv.

 

my 93 si did the exact same thing last week. i pulled the TB off and cleaned it and such, but it still surged. strangely enough, i unplugged the tps all together and it stopped. however, now it idles at 1500 constantly. on the up side though, it stopped revving, so it's a quick fix for now until i find the actual problem. also i've noticed a slight increase in horsepower at 3800 once i unplugged the sensor. i've been driving a week with it unplugged and no problems.

 

MIne does the same thing for a year now, BUT only when the ac is first turned on,....and intermittently. Itll bounce to 1500 then down and back up to 1500,...stop then chill for a hwhile, then starts it up again...NOte: only when AC is on...ANy SUggestions?


J-95SI

 

mine has nothing at all to do with A/C. anytime i don't have a load on the engine it revs, non-stop between 1K and 2K. up and down, up and down, up and down, you get the picture.

 

Yes we bget the picture of you not useing the search button.

 

do the hole plugging thing... it works. i did it on mine after my tps was bad and i changed it.