QuestionQUESTION: My car was stalling as I was driving for no reason. Eventually the check engine light came on. I took it to Advance Auto and they scanned it. The 3 codes were p0725, p0700, and p1391. We replaced the input and output transmission speed sensors and the Cam shaft sensor. Before replacing the cam sensor it ran very rough. when you revved it and let go of the accelerator the tac dropped quickly. when it was trying to stall it was very violent. now it runs smooth and I have driven it around my neighborhood for a few hours and seemed fine.. no check engine light is on now. but then it attempted to stall, yet was not violent this time and did not last long like it did before. it happened 3 times all whiling turning hard right. it seems to occur when pulling off or driving at a steady speed. not when coming to a stop or at a complete stop. Also it has not stalled while in the driveway, while revving or doing anything else. only while actually driving it. thanks. i appreciate any help.
ANSWER: Just answering to clear the question 'pool'; let me know.
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QUESTION: so i disconnected the battery again and then drove it for about 45 minutes and of course nothing happen. But i also disconnected the battery this morning and drove it 2 times for 1 hour each. the first time it stuttered once about 20 minutes in and the second time it jerked hard once at the very first stop sign about 2 minutes it and then ran fine. Still no check engine light but I am not convinced that all is well. i think the cam shaft sensor being replaced helped a lot but was not the root of the problem. I will drive it around for a few hours tomorrow night when i get home from school and see if it happens again. I'll update you when I'm done.
ANSWER: You can check for codes even though no check engine light or even no major stumble. A subtle problem will still set a code. Checking for codes doesn't erase them, only disconecting the battery does that, and I suggested it because I wasn't aware that you had done it recently. I wanted to clear anything that may have been due to the cam sensor. I will await your findings.
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QUESTION: So today my father drove the car. it would start bucking as he accelerated. He picked me up about 20 minutes from where we live and he said it didn't seem that bad. It progressively got worse on the way home. The bucking was more violent and lasted longer. Then the check engine light came on so we stoped at Auto Zone (before I went to advance auto). P0700 and P0725 were gone and just P1391 was left. When i got it scanned at advance they gave me very general descriptions of the codes. At Auto Zone the description was more accurate and stated 2 probable causes: timing belt/chain stretched/jumped OR defective CMP sensor. So tomorrow I will replace the crank shaft sensor and probably take the cam sensor back and get a new one to be sure it is not defective. then i will try the coil pack.
AnswerHi Adrienne,
It may be the cam or the crank sensors not being close enough to the surface they sense. May I suggest that you buy paper spacers for the tip of each sensor and apply it to the tip. Then install them being certain that the tip is touching the inner metal surface that it is trying to sense, hold it their and tighten the retaining screw. That would save you possibly from needless replacement of a sensor.
I can also tell you the wiring of each sensor if you would like to verify that there is not a poor connection between it and the powertrain control module. Let me know.
The coil pack has its own code, so I would not be inclined to replace that absent a fault code (P0350-0356).
Just by chance, did you try a fault code readout with your ignition key and the check engine light?
Roland
