Hey guys...

I'm driving at about 65MPH with the cruise set. There were a couple of what felt like stutters just like a quick little jerk. As I'm getting off the highway minutes later, the Check Engine Light comes on.

I dropped off a friend and headed home. The Jeep seemed to drive ok but as soon as I let off the gas the RPMs would drop to about 500 and then stutter lower and come back up. It shifted fine. I limped it home and in the driveway it died. Started right back up and got it in the garage.

The oil pressure dropped with the idle but never below 20 or 30. Fluids are still full and when it died it started right back up. Check Engine Light still on.

Any ideas before I drop the cash on fixing it??

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Added the codes below...

P0121
P0123

 

Pull those codes my friend! Take it down to your local auto parts store and ask to use their OBDII tool. Tell us what you find out...

 

Planning on that in the morning. :-) Got too late tonight.

 

It threw codes:

P0121
P0123

I replaced the Throttle Position Sensor since it was mentioned in both codes but no such luck.

Any other ideas before I roll this thing into the shop?

 

P0201 is a issue with the #1 injector. Inspect the injector wiring and the injector itself.

P0123 is a TPS issue. Did you clear the codes after replacing the TPS? IF you did and it came back check the wiring and connectors once again. Where did you buy the new TPS from?

 

I lied...

Codes are really...

P0123
P0121

I had been reading and messed up the digits.

I did not clear the codes. I did go through some WOT cycles and it's running better. Not trying to die but the idle is high.

New TPS is from O'Reilly. Closest place to the house that could run the codes and the nearest Jeep dealer is 30+ miles.

 

So the high idle remains in. Runs at about 1500 RPMs in park. It'll idle around the normal 900 RPMs at a stoplight.

Do I need to clear the codes before it will run right?

Is it possible that I installed the TPS wrong? Not sure how that little blade turns the sensor and all that.

Oh yeah... And if you didn't look at my info, it's a 98 Cherokee 4.0 4wd.

 

You should try to clear the codes to see if that fixes the check engine light issue. I don't think it will solve the high idle problem though...

I am thinking that the light will come back on though since there is still problems... So hmmm... Give me just a sec to do some research and ill see what I can dig up for ya(not to famlier with the HO motors more of a renix guy).

By the way did you check and make sure all your vacuum lines are in good shape?

 

Idle actually came back down to normal today. I'm going to try and clear the codes and see if anything pops back up. I'm hoping it's fixed and I'm actually planning to sell. Horrible timing!

Vacuum lines are all good.

 

Cool! Let us know if anything else comes up. How's the oil pressure looking?