QuestionQUESTION: Engine light goes off and comes back on....Started my car this morning and it was running rough, gave it gas and there was no power (Engine light was on, making strange noises- did not drive it anywhere - turned it off. Went back out 10 minutes later- started it up, drove it engine light was off and car ran fine. When the car runs rough, engine light comes on. Next time I start it the car will run fine and the engine light is off! What do you think could cause this to happen? Thanks for your help.
ANSWER: This could be a host of different problems, and the easiest way to narrow them down is to check to see what code(s) are stored in the engine control module (ECM). Auto Zone and AAMCO have advertised they'll read your trouble codes for free.
If I had to hazard a guess, I'd suspect that you're describing a misfire (lack of power from one or two cylinders) caused by a secondary ignition (spark plugs, ignition wires, coils) failure. Often, they're more prone to problems in high humidity situations (or rain).
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QUESTION: Thank you for the information. My husband changed the plugs and plug wires. The light still comes on sometimes but does not stay on. It will go off after a few days. I took it to Autozone when the light was on and the code that came up was P0150. The interesting thing is that when the light is on the car will act like it has no get-up-and-go (for lack of better terms) and then it will take off. Once it does, the light goes off and stays off for many days and many miles. Any other suggestions/ideas? Thank you in advance for your input!
AnswerI'm going to assume you have the 2.7 V6 engine in your Sonata since P0150 will not apply to a four cylinder engine.
P0150 indicates an open circuit in the bank 2 upstream oxygen sensor (the upper one in the manifold near the radiator). This code is nearly always caused by a problem in the sensor itself. Check the wiring going to the sensor. If it appears okay, replace the sensor.
This typically won't explain funny noises or a lack of performance, however. It's possible you may have an additional problem.
