2005 Xrs High Idle, Surging - Toyota Corolla, Chevy Prizm (1998-2008)

Hi Corolla Forum,

2005 XRS suffers from high idling and surging, trying to figure out my idle mystery without taking it to the dealership.

1. took it to a local mechanic who cleaned the throttle body and made it worse than what it was previously, he told me to buy and replace the throttle body - I did not.

2. spoke to couple of mechanics: one suggested I look at the position sensor another one told me to take to the dealership for idle relearn procedure another one told me to take off the throttle body and clean the entire thing

3. I put the OBD II code reader on it and the trouble code said: idle air control valve

4. I replaced the idle air control valve and replaced a dirty filter

Now the car just idles at 2000 RPM's and I'm still having trouble with the idle. Any suggestions? I need help and no mechanic seems to know how or what the problem might be.

Common problem would be a leaky intake gasket - affects the 1ZZ-FE engines much more than the 2ZZ-GE in your XRS, but this is not uncommon on the 2005-2006 Corolla XRS to have idle surge.

Having said that, you've already replaced the IAC valve, which was likely damage by the first mechanic. Depending on what was replaced, the car will have to relearn some preset parameters.

I'm assuming that the ECM was cleared after you pulled the CEL (was P1652 the code?). If you did not reset the ECM - now would be a good time to do so. Car will run a bit off until it relearns, how quickly will depend on how much you drive, how many start/stop cycles, any steady-state driving, etc.

Running 91 octane exclusively - correct? Don't try and run regular gas in this engine, some people say it is OK if you keep your foot out of it, but you'll definitely do damage if you try to. Did they try cleaning MAF and IAT? Would have been at the top of my list to try and clean along with the throttlebody. Those together influence your idle quality the most.

Thanks for the reply,

Replaced the position sensor with no affect. Pinpointed the problem, it is indeed on the end of the throttle body - the spring that shuts the air intake where it meets the cable - the spring is worn out however Toyota does not sell that separately from the throttle body, it's a 2005 with low miles (55K), just a poor quality part. Using a spring to close it shut but it does not fix the problem completely. A new throttle body is $950.

Thanks Toyota! I used to think Toyota made the best car, now I'm seriously wondering if I ever want to buy a Toyota again.

This seems to be a complicated issue which a new friend at the dealership thinks is software related rather than parts.

I have a 2003 Pontiac Vibe GT with 2ZZGE engine. This past weekend I cleaned the throttle body and IACV (idle air control valve). I did a complete throttle body removal and also removed the IACV from the throttle body. Everything went perfectly and was cleaned to new condition.

Exactly what I did: https://www.celicahobby.com/forums/u...rly-clean.html

PROBLEM: when I performed the clean I made sure to disconnect the negative terminal and I was disconnected for at least 4 hours (I was also replacing the oil pan gasket). When I finally started the car it idled at 2000 rpm. Once I actually drove it and then clutched to return to idle or put it in neutral the idle was 3000 rpm and a quick gas pedal flick would cause it to drop down and begin an idle search where it surges the rpm from 1500 - 2100. Sometimes this doesn't stop till I put it in gear and drive again or sometimes it finds idle at about 2000 rpm. I can also tell that while the vehicle is driving that there is throttle without my foot on the pedal.

I spoke with my new dealer friend and pulled my EFI fuse and relay for 1 hour with no change, so I left my car overnight with the EFI fuse pulled and still no change. I confirmed that when the surging is going on, that the throttle butterfly is fully closed and not moving. This means that the IACV is indeed working and is what's causing the surge. Like I said, the IACV is mechanically moving but it refuses to relearn proper idle.

The only thing I can find that is pretty much exactly what's going on with my car is this video were a guy has an MG that surges just like mine and he does a manual idle relearn through a pedal press/ignition on/off coded process. I've asked the dealership if there is a manual idle relearn override and they've advised that it's supposed to automatically relearn idle after ECM or EFI was not powered for at least 1 hour.

MG video:

Just to be clear:

Throttle body is perfectly clean and butterfly is not restricted or not closing

TPS (throttle position sensor) was not adjusted or changed in anyway during cleaning

No engine codes or engine lights are present

Throttle cable is fine and tension is good