Q: Can an open gas cap which causes the Check Engine Light to come on cause the car to not start and the ECM to appear bad?

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Gas cap was left off. Check engine light came on after a couple days and stayed on for approx 3 weeks. The day after the check engine light went off, the car shook while driving, then lost power, and eventually would not restart when turned off. At first the car symbol with an exclamation point in the center lit up, then other lights when the car wouldn't start. Was told that the ECM needs to be replaces. Concerned that it may need to be reset and not replaced or that there could be a fuel issue causing the problem.

My car has 147900 miles.
My car has an automatic transmission.

Yes, there are a lot of things a bad gas cap or open gas cap can affect. If you don’t have a gas cap then you may be experiencing issues with debris getting into your tank or fuel filter and affecting the drive performance. Since the ECM is a costly repair, you may want to have another independent technician diagnose the vehicle’s loss of power. They will be able to confirm the cause of the issue or advise you on another fix.

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