High idle

Few weeks back I got the P0120 code. I ordered a new OEM TPS and IAC, today is took apart the throttle body cleaned everything best I could and put the new parts on. It’s now idling at 1500 constant. Any thoughts?

 

yes brand new oem parts.

if I unplug the IAC the idle drops to about 950 if I plug it back in it idles up to 1500

 

I haven’t cleared the codes. I will drive over to the auto part store and do that

 

Those IAC valves can be finicky, I cleaned my throttle body once and some crud washed down in the IAC.. took it off and cleaned it and its idled fine since. Sounds like its working since the idle speed drops when you unplug it. You will have codes for it since you unplugged it.. Id get those cleared first and drive it and see what pops back up.

 

Cleared the codes. Still idling high. Going to order new vacuum lines next mine are all pretty crappy.

 

Did the light come back? My next suggestion was gonna be double check all vacuum lines. I don't know but i wonder if the TPS needs to be set when you install it? Some need adjusted to a pre-set voltage when you install them.

 

nope no light. How do you set the tps?

 

I don't think these are adjustable. On some you turn on the ignition and use a multi-meter and as you turn the sensor in place the voltage will rise. That's how the ecu knows where the throttle is. But like i say I don't think it applies to these after doing some quick checking.

**Try popping your air cleaner housing off and making sure the butterfly valve is closing completely. Some of these have problems of the TB wearing and allowing a tiny amount of air around the butterfly. Especially if its been cleaned as the gunk that helped seal it has been removed.

 

Well after driving it around for a while I pulled up to a stop light pushed the clutch in and it idled down to 800ish.

 

It’s been 5 days since replacing these things and the idle is at 750 now. For future reference if anyone has these issues and replaces the stuff I replaced drive the truck 50 miles or so afterwords so the computer can relearn.

 

I have a 1st Gen 04 PreRunner 3.5V6 - Took off the throttle-body and cleaned all the gunk out of the entire throat. Was unsure as to pulling what I thought was the IAC cover off to clean it. There are two access points. 1- Two screws through what appears to be a very-slightly adjustable cover over a small valve(?) that can move very slightly fore or aft, and 2.- a larger black plate on which the aforementioned cover is screwed that is secured to the TB by six or so screws. I couldn't get the last screw out w/o stripping the top out, so I didn't. . . put everything back as it was, but not sure if I got the two screw cover on in the exact same spot. Would this affect my idle (starts high around 1500, dropping to around 900 when warm). Would pulling the battery neg. cable off and letting it set a bit possibly re-set sensors I unplugged to off the TB. . . . ? ? ? ? Or did I screw up an adjustment with that small cover that has elongated screw access holes? Thanks for any help..

 

Same thing happened to me, disassembled and cleaned the TB and after I reinstalled it my idle was at around 1200 RPM. After a day or so it returned to normal.

If it doesn't return to normal, that could mean that the inside of the throttle body is worn where the butterfly valve is and by cleaning it there is now a gap that is letting excess air through. In that case you'll have to get the throttle body rebored

 

1,500 RPM seems hight but exact same here ^^

 

Did you disconnect the battery while you were doing the work?

Wondering if that would have cleared it to learn faster.

 

no