Hey guys the other day my jeep started idling high when it was cold (1000 rpm) and after it warms up it goes down to 500. I already cleaned the IAC with no results. Just seems weird as it has never done that before even when cold.
Idle is controlled by the PCM on our TJs. It's possible it could be something such as a small vacuum leak. However, mind does this from time-to-time as well with only 57k on the odometer. It only happens when it's really cold and been sitting a long time though. I personally don't pay any attention to it. I just think of it as normal.
TJ2
TJ Expert
Could be a faulty TPS as well.
When the idle is too high, how is your braking? Does the braking feel any different during those times? As in is it harder to brake during those times?
When the idle is too high, how is your braking? Does the braking feel any different during those times? As in is it harder to brake during those times?
TJ2
TJ Expert
Yeah, it will stay high then if there is a vacuum leak. I say it is not a vacuum related.
My braking feels fine but I will double check again today. I also thought it could be TPS but to seems odd that it doesn't always run high
If the braking is affected when it's cold and idling high, then to me, that would indicate a potential vacuum issue.
When there is a vacuum leak, that raises the rpms which can also affect the power brake booster which is vacuum powered
When there is a vacuum leak, that raises the rpms which can also affect the power brake booster which is vacuum powered
Mine idles around 1000 rpm when cold then drops to 750 rpm when warm.
@02GreenTJ it sounds perfectly fine to me.
It wouldn't hurt as a PM anytime to double check the vacuum fittings around the intake manifold. Those rubber fittings don't last forever and they are heat forgiving but only up to a point, then they become rigid and start leaking.
@02GreenTJ it sounds perfectly fine to me.
It wouldn't hurt as a PM anytime to double check the vacuum fittings around the intake manifold. Those rubber fittings don't last forever and they are heat forgiving but only up to a point, then they become rigid and start leaking.
I'm having the exact same problem except it's idling at 2500 when cold and drops to 500 when warm, only happens in winter on cold days (sub 10 degrees Celsius), this is the second winter it's happening, was fine all summer, anyone work out the issue? Worth replacing the TPS?
I ended up buying a new TPS and idles absolutely fine now, even on cold mornings when the temperature is below 10deg Celsius
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