Join Date: Jan 2008
Location: Mexicali, Baja, Mexico
Intermitent high idle
It has been a long time, I never posted a lot really, but I did read all the interesting things you guys post.
Need help here!
My idle is acting strange:
Whole story short: Idle was erratic so I've just cleaned my TB good, including IAC (The pindle was all the way out and it was stuck, could not retract it), reassemble with a new gasket.
First question: Does the IAC pindle was in "normal" position? I've read all these threads regarding IAC valves, but none of those specify how does a good IAC valve should be when removed from the TB.
When cold, it idles smoothly around 600 RPM in "D", the tranny works silky, but when it gets warmed up, it races almost proportionally up to 1100 RPM in "D" (2000 RPM in "N").
And when I hit the brakes to get to a stop, the car downshift late and I get a nasty bumpshift....It is really annoying!
I checked the codes and I get a 12-25-55, I know i should Not worry about 12 & 55, but the 25 (Which refers to the IAC valve circuit). I thought it was for the cleaning I did to it, hence the PCM reset as a first option on the possibilities list).
The possibilities I'm considering are (In order of importance):
1. PCM reset (Disconnecting negative terminal for 15 mins?)
2. IAC valve (Given that the pindle should not been "out" when
removed...But then the variable of working fine when cold/ high when
3. ECT (Engine Coolant Temperature) (Since the problem occurs when
the car when to Normal operating temperature and this sensor affects
the air/fuel mixture)
4. Vaccum leak on the Intake Manifold gaskets (UPPER/LOWER) (Since
I've read that some of you had this same problem, I haven't performed
the unlit propane torch check)
5. TPS sensor Bad or not calibrated (However, the RPM needle is steady
when you pump the go pedal and the problem is intermitent, not sure,
some people post it can be calibrated, don't know for sure).
6. EGR tube gaskets (Also read it here)
If someone had this kind of problem please let me know how did you solved it.
I feel that the IAC valve has to be replaced, but those are $60 I don't want to spend if it's not gonna fix my idle.
Thanks in advance!!