hi guys. im new to this website, and to civics. i bought a civic coupe 1998 about a month ago and since ive got it the revs go up and down continuously at idle when warm. ive been opn a few trouble shooting sites and these said to replace either the MAP sensor or the TP sensor. ive done both and no luck. also another wierd thing is that i inplugged the map sensor and it stopped, i unplugged the tp sensor and it stopped, i also unplugged the injector sensors 1 by 1 and it stopped every time. has anyone come across this problem before?
thanks. brendan.
p.s sorry 4 the essay!!!

 

You may have a vacum leak some where. Also, try adjusting the idle via ICV on the throttle body.

 

also check the idle air control valve on the back end of the intake manifold. those things get clogged up. are you getting a check engine light?

 

thanks for those tips, ill check them out. no, no engine light either. thanks again.

 

i have the same problem my local speed shop said it was the iac so i went to the junk yard got 1 n cleaned it up still had the same problem. i went to honda n got 1 brand new n i still go the same problem. i loosened the hex screw in the end n now its not that bad but i don kno wat else to do.

 

check your throttle cable, free movement, etc, and that its not over tensioned, when the throttle is closed there should be a little slack iof its tight at all it cunfuses the ecu and sensors, if thats not it, try cleaning your injectors next...