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98 Riviera has intermittent miss

08-31-2009, 06:54 AM
The dealer read the service engine codes and replaced both the crank and cam position sensors. I found a chewed off vacuum line and replaced that but the engine light still comes on indicating the crank and cam position sensors. Could they both be defective? The spark plugs and wires have also been replaced. What else could be causing this. I read something about cleaning the top end with Seafoam but the web link to the procedure didn't work.

09-06-2009, 09:54 PM
Were the DTC's cleared after the work was performed? If so, you could have other problems like fuel injectors, low fuel pressure, clogged cat, loose/corroded pins on the ICM terminal, or one of the coil/plug wire terminals not completely snug.

08-08-2010, 05:33 PM
The makers of this car still can't fix it. Frustrating to say the least. The crank and cam sensors have been replaced, one ignition coil replaced. The service light came on and the code was "cam position sensor out of range". The cam sensor was removed and tested and no problem was found. Now they think it might be the ignition module but it seems to be a trial and error method of testing it. It's coming up to a year since this problem started and the problem isn't going away, just my money.

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