Cold is F'ing with me

[Lothos]

Today and a few days ago when it got below freezing, my engine would stick at a certain RPM unless I shifted to neutral and redlined it a couple times usually until 15 to 20 minutes after it reached full warmup temp. I use a block heater in the winter which lets the temp guage say its warm inside of 10 minutes of driving, but I think the entire engine is not actually warm yet. Obviously its an electronic device thats not liking the cold, but any ideas?

[GMCsonoma94]

this is a jeep 4.0?

[Lothos]

yeah, 2003 rubicon.

[GMCsonoma94]

check your idle air controler

[Lothos]

How about MAP sensor?


"If a vehicle is started and driven to a
very different altitude than where it was at key-on,
the barometric pressure needs to be updated. Any
time the PCM sees Wide Open Throttle (WOT), based
upon Throttle Position Sensor (TPS) angle and RPM,
it will update barometric pressure in the MAP memory
cell. With periodic updates, the PCM can make
its calculations more effectively."

The condition i am seeing is the engine does not decrease in throttle upon lifting off the pedal below whatever point it decides to stick at. Typically its been about 1500 rpm.

[blizazer]

Your engine is also going to idle higher when its cold, to make it warm up faster, and meet emissions faster.

How fast is it idling?

How is it obviously electronic?

A sticking throttle cable or plate could cause this too.

[Lothos]

It's not an idle that's happening. Because 1800rpm is not an idle for an automatic and it can sometimes stick at like 2700rpm. Since my drive to work is done between 35 and 50mph, I am rarely stomping on it over 2500rpm. When I am heavy on the brake to hold the vehicle at a stop, something's a miss. The cable is fine, first thing i checked. I've had alot of sensor problems in the past which is why i jumped on the electronic issue, but it could be the Idle Air Control Motor though.

[Haggar]

The map sensor can cause funny idles up around 2000 like that. Sometimes water/dirt/mud can block the sensor hole on them.

[Yetti]

If its hanging up while driviing and acting like cruise control its sounds like the throttle plate is holding the TPS in a frozen position. it could be you have modified air intake like air raid or some thing that is letting in way to much cold air, or you have a worn throttle plate and its creating a high spot that is freezing in place because of a high velosity air moving threw it. check everything twice you don't need to have an accident

[Lothos]

Update: turned out to be nice and thick frozen Mounds mud on the throttle return spring :)

On another note, my starter is misbehaving.

[Bones]

the starter is most likely the mounds mud too

[Lothos]

I suspect, but its so damn cold out I don't want to pull it.