Another High Idle post...advice please

[vallentinerocks]

Today my idle changed to 1500rpm. idle was around 800rpm which i believe is normal. just got the car last week and before and after new plugs,wires and pcv,motor flush and oil change the idle was always the same,right around 800. later today it started idling at 1500 and wont go below that. Ive read the back posts. Likely to be IAC but want to get input before buying the IAC valve if i dont need to. Should i try resetting the computer first and if so is this done by disconnecting the battery for a short time? should i spray cleaner in the throttle body to see if sticking?

I did a few checks on the idle air control valve already. When engine is running(1500prm), i disconnected the 4 pin plug and the idle did not change at all, stayed high at 1500rpm. Also, the Chilton manual says to check resistnace with ohm meter. readings should be 40-80 and mine where at 55 respectively. Could the IAC still be sticking mechanically even with proper ohm readings?

Also after putting the old IAC back in (did not clean the inside or anything,just inspected), on first start, the car would not idle up or stay running. I did the reset for IAC as explained in the manual (tap gas pedal,turn motor on 5 sec,turn off,wait 10sec and start motor). Motor rpms kept motor running again but still back to 1500rpms. I let the car warm up of course and still rpm's wont come back down to normal 800 range. Turning on AC doesnt do much to the high idle either.

Should i go head and spend the 40 bucks on the new IAC or should i try alternatives first?

[Shirl]

Try cleaning out the inside of the throttle body with gumout or another cleaner and a rag. There is probably a lot of carbon build-up in there.

[BobbyZ72]

My iac had lots of carbon build up on it, and where its sits inside the intake also. Take the iac out again, and clean it, i just used wd-40, spray, wipe, spray, repeat till cleaned. It cleaned it up like new. Take off the Throttle bode, remove maf and hose it down with carb cleaner, let it dry and finish with hoseing it down again the throttle body cleaner, this will lub it up and make it nice and shinny, also spray down maf with the throttle body cleaner also, mine had lots of build up on it. After putting mine back together, she ran and idled better then i thought was possable. Go to my car page below of a few pics.

[StrtRacer98]

Check out my cardomain page 6, for removing your throttle body and cleaning it properly

lots of pictures and step by step walk thru,

good luck

[vallentinerocks]

thanks for the suggestions on the throttle body. first thing i did was disconnect the battery to reset the computer. also inspected the IAT with the two wires that pushes into the induction tube. anyway, connected the battery back up, started, and my idle is now back to the normal range so that worked for now, unless it was still a sticky IAC that just decided to start working properly again. Not sure but my idle is back to normal.

If it does it again, i will probably go ahead and replace the IAC with a new one. Ive read on this forum about MAF,EGR and other other parts and sensors that might be bad that could cause high idle issues, but if the car is running smooth and no other problems, could these other components be faulty?

[BobbyZ72]

just clean the iac, before you replace it. clean it in the way i said, i think you wil be fine.