Chevy Uplander 3.9 hesitate when accelerating

hockey4everhockey4ever Member Posts: 3
edited February 2015 in Chevrolet

In the morning, when i go to pick up my news paper at local convenience store, the van is running rough and hesitate when accelerating.
When i take the van 1 hous later, it will run smoothly and there will be no hesitation and i will be good for the rest of the day.

If i skip the trip to convenience store and the first thing in the morning i do a long trip, let's say 2 hours trip, the van will run rough all the way during those 2 hours.

When the van is running rough it will stay in this state until it's turned off, wait and restarted again.

When the van is running soothly, it will stay in this state until next morning.

While driving, it never happened that the smooth running engine became running rough and the opposite is also true. It never hapenned while driving that the rough running engine became smooth.

I suspect that at engine start up, a parameter is stored and kept in memory until the car is turned off, wait and restarted again.

DTC code P0336 and P1174

Any idea? Leaving in a cold climate in Montreal Quebec aera. Thanks


  • hockey4everhockey4ever Member Posts: 3
    This week end, i plugged in my osb2 scanner and i monitored the rpm sensor while the engine was running rough. I was not able to get any signal.
    I was getting signal from other gauge like coolant temp, mass sensor but not from RPM.

    Am i right to assume the rpm gauge in my obd2 scanner is getting the signal from crank sensor?

    RPM gauge in instrument panel cluster (dashboard) was showing correct RPM. Is it related to crank sensor?
  • hockey4everhockey4ever Member Posts: 3

    Crank sensor just got replaced. Now it always hesitate when accelerating and it always run rough at idle. Intermittent problem became constant.
    CKP variation relearn procedure was not done because I don't have a scan tool for this. Should I bring it to the shop? Can I do it without the scan tool?
    Do you think it's the cause of my problem or it is something else? Thanks for your help
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