How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Chris Your Own Question
Chris, Shop Foreman
Category: Jeep
Satisfied Customers: 13471
Experience:  Jeep Certified Master Tech
Type Your Jeep Question Here...
Chris is online now
A new question is answered every 9 seconds

Jeep problem, same thing today. My Son works at a repair

Customer Question

Hi Chris, Jeep problem, same thing today. My Son works at a repair shop. Anyway, we had a real nice "Snap-on" Scanner... No codes, saw the "CMP" & "CKP" as it was running, the jeep sat for over 6 hours after it died again.... then it started after we got
it off the flatbed. It would not stay idleing.. had to keep the foot on the gas. anyway- no codes, the counrter for cmp & ckp were steady- the grapgh showed a constant even cycle, I noticed the "counter numbers were all over the place though. Would a bocked
fuel filter show any codes? and I'm thinking of replacing the CKP crank sensor ? anyway.. whats your thoughts? Thanks, ***** *****
Submitted: 1 year ago.
Category: Jeep
Expert:  Chris replied 1 year ago.

Hi Paul. This sounds like the PCM itself. No codes makes me think that the PCM shut down. If you had a cam or crank sensor code, then I would say replace them. But since you have no codes, go with the PCM.


Customer: replied 1 year ago.
Just wondering, if that is it the "pcm" would it still run, but not idle? It won't start now anyway, but it may in the morning,??
Expert:  Chris replied 1 year ago.

Well here is what happens: When the PCM shuts down, it's memory gets erased. It has to relearn the idle strategy and if the throttle body is dirty with carbon deposits it reduces air flow at idle and that is why you have to keep your foot on the throttle to keep it running. If you were to clean out the inside of the throttle body with some spray throttle body cleaner, then it will most likely idle on it's own after a PCM shut down. Hope that makes sense!


Customer: replied 1 year ago.
OK, I'll Try a Few things like that, I'll let ya know,, thanks
Paul H.
Expert:  Chris replied 1 year ago.

Sounds good Paul!