ok I have a 1.5 non vtec in my del sol. I have an idle surge of course when in park or neutral. I have done the following things

1. replaced the IAC valve with 2 different valves I knew worked fine.
2. Pulled the throttle body off opened up the Fast Idle Valve and tightened it back down.
3. then replaced the FAV with a new one.
4. I have bled the coolant system each time a component was removed.
5. sprayed brake cleaner all around the intake and hoses
6. clamped off the hose to the brake booster


I am at a loss, I CANNOT figure out where the problem lies, I have completely rebuilt this motor from the rings, to bearings to seals and gaskets, etc and still I have this annoying surge. It makes me not want to even drive the car, so if anyone else has a suggestion, please LET ME KNOW ASAP BEFORE I TURN THIS CAR INTO A CLUNKER

 

any ideas from anyone?

 

Any CEL codes?

If you pull off the intake and use your finger to block the throttle body port leading either to the IACV or FITV, does the surging stop when the engine is idling?

Is the engine overheating or is there white smoke in the exhaust?

Have you multimeter tested the TPS and the 2-wire ECT sensor under the distributor.

 

yeah we did all of those things.

I actually figured it out finally. The throttle plate had to be adjusted. when you let off the gas the plate wasn't closing completely, so I am glad thats over with, now I can move on to an exhaust rattle and leak ha ha

 

Makes me want to try this.

I'm having the surging problem too and it really does make you want to junk your car for good.

 

I had a huge rattle in my 91's exhaust. Took awhile to find that it was the inner and outer pipes rattling around. Had to drill like 20 holes in the outer pipe and then weld the hole .. thereby welding both pipes together to stop the movement.

 

Like RonJ said, check your TPS.

It is actually a pretty common cause of surging idle and often overlooked.

You'll just need a multimeter to check your WOT and idle wires for proper voltage.

WOT should = around 4.5v
Idle should = around 0.45-0.49v

 

Thats what i got when i checked.

 

I have a 1997 Acura 2,2CL M/T with 125K miles. I cleaned my throttle body (and the associated components) and IACV to improve performance. There was nothing wrong with my idle before this procedure. When I started my car after reinstaling, everything was fine idling at 850rpm. I took it out for a test drive and when I came back and parked the engine rpm started to fluctuate around 1500 rpm. I remembered that I didn't bled the cooling system so I did that and then the rpm stayed around 1000 rpm. I thought it could be a vacuum leak and replaced all throttle body gasket and IACV o-ring. Now the starting rpm is around 2000 and it fluctuate between 1800 and 2000 rpm. I have done this 3 years before without any trouble. Now I see smoke (guess vapor) coming out of my exhaust. Is this something to do with air in the cooling system or IAC, FTV or TPS could have failed because of my cleaning? The reason why I did the cleaning was my mpg dropped from a steady 26.5 to 24 for the past two tanks.

Please help! This is my daily driver.

 

Yeah, I had the same problem too after cleaning. I thought my IAC got damaged after cleaning so I bought a new one from an OEM Honda store.

Still had problems so I losened my throttle cable & re adjusted my idle screw (was to high) and it has seamed to solve my problems *knocks on wood*

 

i had the same problem in my hatch but after i adjusted my idle screw the surging went away at idle but as i tried to test drive it, it started surging under acceleration. i have done all these steps above. No luck so far