Random Idle

[sinus19]

yep, another Idle thread.

Soo.. in the cold mornings my idle tends to go bazoonkle when ever it feels like till the temp hits 200 for a few minutes and then the idle surge stops. It will start find and rev at 900 as any other cold start. but then out of no where it will spike up to 1200, 2000, 1000, 1500, and then back down to 500 randomly. not only does it do it while its parked but when it is moving as well. I've replaced Map, IAT, & TPS with no luck. I've also tried reseting the TPS by turning the truck of pulling the plug, replug it (battery) open the throttle body all the way 3 times slowly etc etc (i dont remember the exact steps, it was a while back) and none of have worked. Its starting to get frustrating. i do have the following codes P0442 and P1538 (dont know if its cus i havent filled up my A/C since the motor rebuild and left the wire unplugged, didnt need it during winter anyways)
Could the Evap leak (P0442) be the issue? dont tell me it could be the stupid Gas Cap lol

On another note.... wat is the stock suspension height (Fender to tire) on an 04 RC?

 

[sinus19]

Anyone?

 

[6speedquadcab]

I've had had the same issue but it happens randomly. I'm hoping someone answers cuz I too have this problem.

 

[Slitherbeast]

Seems the IAC stiffens up. some have some success with loosening it up with penetrating oil.Or simply get a new one. Do you have a catchcan?

 

[Engin89]

Need to tell us year / QC or RC / Mods. etc. would help.
Have a similar issue with tach cluster, mine being a known problem on 06' RC's.
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[Slitherbeast]

P1538 code is for a vacuum leak. it is probably on the evap system.

 

[6speedquadcab]

2006 QC no mods.

 

[shorty]

PO442 is also a EVAP leak. Mine throws that code every time the fuel take gets below 1/2 (often), I reset and all is well. It does change my idle but not to the extent yours is changed. Scott thinks I have a pin hole or crimp in the hose (what hose :dontknow and a smoke test is what I need to fix the problem. Cheaper to reset and drive on.

 

[sinus19]

Interesting.... seems like ya'll think it might be an evap leak. I will check the A\C and and spray some good ol WD40. If that dont work ill have to take It in and have them do a smoke check, are those spendy?

 

[sinus19]

Need to tell us year / QC or RC / Mods. etc. would help.
Have a similar issue with tach cluster, mine being a known problem on 06' RC's.
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Sorry, its an 04 RC

 

[sinus19]

Okay...so i told you guys the wrong code its actually P1598. Ive checked the A/C and it spins just find. Also, yesterday it rained all day and it was about 45 deg. And my idle was all over even at 200 deg. (engine temp) when the temp out side is around 60 it doesnt act up. i am at a complete loss. the weather obviously has something to do with it.

 

[Slitherbeast]

Code 1598 is a to high idle rpm code. It will disappear when you fix the elusive vacuum leak!

 

[sinus19]

Hmmm okay...ill keep looking Then

 

[sinus19]

Is this supposed to have a hose attached to it?

 

[Engin89]

Code 1598 is a to high idle rpm code. It will disappear when you fix the elusive vacuum leak!

Had a vacuum leak. Under the manifold. Installed a vacuum gauge.
19 ''s at idle, at 850 on the tach.

 

[sinus19]

So i took the A/C relay out and what do you know, the idle surging went away lol