i drive a 99 civic with a d16 and the idle seems to bounce up to 2000rpm and back down to 1000rpm. this happens when i idle and after driving for a little bit. at times it jumps up to 2000 and then idles properly. but most of the time it jumps to 2000rpm and then 1000rpm over and over again.
when it continues to bounce i turn off my engine and restart it up and it idles ok.
what could be the problem?
is it a vacuum leak or a IAC sensor bugging out?
or the temp sensor?

 

I dont think that its a temp sensor. It could be your iacv, disconnect it and blow it out with some air or brake parts cleaner and plug it back in.

 

same problem with mine....

 

It could be the TPS. I'm having the same prob kinda... Mine jumps from 600 to 200 (yes i know its not 200, but the damn gauge says so)

Anywho i just bought a TPS from Kteller and we'll see tuesday if it fixes the prob.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by yoffer &raquo;</TD></TR><TR><TD CLASS="quote">I dont think that its a temp sensor. It could be your iacv, disconnect it and blow it out with some air or brake parts cleaner and plug it back in. </TD></TR></TABLE>

x2

This is a very common problem on Honda motors. Are you getting any CELs?

 

Either bubbles in your coolant or it's your IACV..

I'm guessing it's bubbles in your coolant!~

 

had the same problem with my car. cleaned the iacv and now it runs fine. try that for sure, its a easy fix.

 

wanna know

 

remove your iacv and screw the big white plastic thing back in if it is out and clean it then put it on and bleed your coolant to remove all bubbles, that plastic thing inside is known to back out after a while once it gets worn out

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ej1sir16 &raquo;</TD></TR><TR><TD CLASS="quote">remove your iacv and screw the big white plastic thing back in if it is out and clean it then put it on and bleed your coolant to remove all bubbles, that plastic thing inside is known to back out after a while once it gets worn out</TD></TR></TABLE>

You're talking about the FITV and the only form of a FITV on a 6th gen Civic is on the Y8...but it's not constructed like the FITV you're talking about.


OP: Have you tried playing with the idle adjustment screw, or anything for that matter, in an attempt to fix it? Had you done some maintenance recently and then this started?

 

Surging idle could also be a vacuum leak.