QuestionQUESTION: Hi Jan:
My 2002 is having the exact same problem. Last night the car began to sputter and also idle roughly when stopped. The check engine while driving will flash depending on how bad the stuttering is. Every so often the car out of it and accelerates normally. I've known for several months that the cat needs replaced. It has made a rattle when cold. The car now has a larger rattle that doesn't quit. I also found the downtube of the exhaust red hot when I popped the hood after driving approximately 8 miles in the city.
Unlike the above poster, my car is not still under warranty. So all diagnostic work is out of pocket. The dealer has really drained my cashflows in the past and I'm still searching for a good local mechanic. I'm considering doing the work myself.
Is it possible that the engine is simply misfiring due to a bad a coil and that this new issue is completely unrelated to the exhaust and cat?
Thanks for any assistance.
Best, Cort
ANSWER: If the check engine light flashes that means there is usually a code stored which can be read out. The stuttering is possibly due to a coil pack, you can check how things are running by taking a look at all the plugs when the problem occurs. You can see which plug leads come from which pack, so when you do this look for plugs that maybe look like they have a little more soot or deposit on them, and see if you can correlate this to one coil pack. If all the plugs look the same, you may need to look for a fuel pressure issue or a faulty crankshaft position sensor; there a many reasons why a car stutters, and the correct diagnostics, unfortunately, take most of the time, usually the fix is fast. Some garages apply lots of fixes, charge the customer, we call this shot-gunning the problem. It is expensive for the customer, but tends to save the garage time. Good mechanics will think about the problem and diagnose it by discounting areas through simple tests to confirm where the problem is, not the symptom. Let me know what you find by looking at the plugs, then we can do some more tests to see if it may be a fuel issue such as a mass airflow sensor etc... Jan
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QUESTION: Thanks for the quick response Jan!
I've been thinking a little more.. I had the coils replaced about 20K miles ago, can't imagine them going already.
The past few days twice I've been financially forced to drive the car well beyond the point of needing gas, relying on the actual needle and not the computer. Once the computer reads zero miles I can travel an additional 15-20 miles. I'm beginning to wonder if this problem is a result of possible water (heavier than gas) drawn into the system from the bottom of the tank. I know the coils have nothing to do with fuel. Before I start pulling spark plugs what would you think about running a quality injector cleaner and/or dry gas through?
AnswerOf course you can do this, it never hurts but note that water is heavier than gas,and the fuel pickup is in the bottom of the tank so it is probably not a water problem, but to run the tank almost dry is likely to get some air bubbles into the system which will cause issues with the fuel metering. So fill up, use the fuel additive and see if the problem vanishes... Let me know, Jan
