I have recently purchase an 1999 Acura CL 3.0 with 176,000 miles on it for only $500. I knew it had some problems but for $500 I figured I can just fix the minor problems it has and be on my way, but these problems are giving me a bit more trouble than I expected.

Since I have had the car the first problem I'm trying to fix is the surging idle, as soon as I start the car up it surges up to 2500rpm's then falls down to 1500rpm's then jumps back to 2500rpm's then falls back to 1500rpm's and just repeats this cycle endlessly. Even when I put it in drive or neutral it still surges.
Also I just thought I would mention that the exhaust stinks slightly and smells like the car may be running a bit rich.

Now from what I have read online you would think this is just the IACV acting up, but after cleaning up the IACV and putting it back on nothing has changed. I went out and bought a brand new IACV and put it on the throttle body and there is no difference, the engine still surges the same way.

Does anyone have any idea what else might be causing this, I would really appreciate any ideas and suggestions this is a really love this car and want to have it running normal.

 

I just thought I would also mention that if while the car is running I unplug the IACV the car will idle at 1500rpm's but not smoothly, it will be kind of bouncy but stays at 1500rpm's.

 

Could my problem possibly be from having air bubbles trapped in the cooling system or from the coolant sensor, possibly a vacuum leak? any help will be greatly appreciated.

 

I would look into clogged EGR passages--the surging idle sounds like a classic symptom. That's what my brother's car did and all the passages for Exhaust Gas recirculation were clogged in the intake manifold.

 

ill try that and see if it works thanks. Ill let you know what happens.

 

I cleaned out the egr ports on the intake plenum and the port that goes directly to the egr valve. The problem idling problem is still here. I'm thinking that the ecu may be screwed up or the wiring for the IACV is faulty.

 

If it's not your IACV, it's probably your TPS

 

Best of luck fixing the issue.