miraclemax

Hi all!

I have a 2013 auto with 92,000 on the clock.

I recently have had two issues. And I’m not sure if they are related.

First is- at cold starts, on cold days, i get a hesitation at around 1600-1800 rpm. I don’t think it is the transmission, because when i slap the auto into gear selection it still does it, and does it before i shift it.

It only happens at cold starts after sitting all night or for long periods where the engine completely cools off after hours of sitting in the cold.

As soon as it’s warm and get a few shifts under it. It’s fine. And doesn’t do it anymore.

I thought it might be the throttle body all gummed up. So i took off the intake, and cleaned the throttle body and put in a new air filter. It did seem to help a little, but it still does it.

My other issue.

The Jeep seems to be eating or leaking coolant. My friend noticed it the other day when i picked him up, he said outside the Jeep smelled of a slight coolant odor.

I checked. And sure enough it was very low.

I have check all over the engine. And can’t find any signs of leaks anywhere.

So that got me thinking maybe it was a bad head gasket. So i rented a tester, that puts a tube over the radiator opening that fills up with special fluid to detect exhaust gasses. I did the test a couple of times and it passed.

So i feel it’s not the head gasket.

I’m not sure if these two things are related. But I’m confused on where to go from here.

PLEASE HELP!

Mr.T

Regarding the coolant leak, I'd add some UV dye to the coolant and look for the leak with a UV flashlight. Both items are in autoparts stores, Amazon, etc.

rob_engineer

Hey- me and a couple other people on here have had the stutter, or hesitation with 2012 jkus in the same rpm level you mentioned. We replaced the Crank position sensor that is under the Jeep, kinda near the passenger front tire region. The stutter was instantly solved. I suffered wth the stutter for about a year. The crank sensor solved it and it never came back. No codes were ever thrown. The crank sensor is fairly cheap and takes about 5 minutes to install.

Asinine

Try feeling under the water pump intake for a small leak. It's small enough to be wet and smell, but not enough to drip. I added a second hose clamp to fix the issue.

miraclemax

Just threw a check engine light

P0128 Thermostat Rationality

miraclemax

Just threw a code

rob_engineer

I don't think that is at all related to the hesitation.

MTNBKR

Had that same code a few times with engine hesitation but not in your rom range. Change the sensor. Really easy to do and a $26.00 part at auto zone. That will take care of the code for sure and may help the hesitation. If it doesn’t, then try what rob_engineer suggests. Good luck .

miraclemax

Just replaced the thermostat housing and the crank position sensor.

Hesitation still there.....

Seem to be just in first gear. Right around 1700-1900 rpm.

I used the auto in the side gear selection and started off in first. And boom, there it I was.

rob_engineer

Please confirm you replaced the crank position sensor and not the cam position sensor. The one I replaced was on passenger side, bottom, not far from the front passenger tire.