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Q: Flashing Check Engine Light is on. The engine shakes at idle and has low power.

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My car started to shakes like a a piston isnt firing? How would I know,if is a dead cylinder or a bad coil I recently replaced sparkplugs and oiil I know it could be mechanical or electronics so I would like to know which order should I tske to diagnose the problem

My car has 170000 miles.
My car has an automatic transmission.

A: Hi, the first task is to extract the proble...

Hi, the first task is to extract the problem codes which are causing the Check Engine light to flash. Most auto parts stores will do this for free. I would suspect plug wires next, and check the condition of the distributor cap and rotor while checking the plug wires.

Pull one plug wire off at a time, then start the engine. If disconnecting the plug in one specific cylinder does NOT make a difference in how the engine runs, that plug wire is your first suspect. With the age of the car, and your mileage, replacing all of the wires is the right decision, even if only one wire is bad.

To avoid any unnecessary repairs, I would recommend having a misfiring inspection completed by a mobile, professional mechanic, such as one from YourMechanic, to diagnose this problem, get an accurate assessment of damage and cost estimate for repairs.

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