Engine light on mechanic checked code p0302 Changed coil for cylinder 2 changed plugs. light still comes on . Engine not running really ruff. Any suggestions
My car has 26400 miles.
My car has an automatic transmission.
Diagnostic Trouble Code P0302 is not necessarily caused by a bad coil or spark plug. Unless the coil was actually tested, it could very well be perfectly good. Diagnostic Trouble Codes do not conclusively identify faulty parts. The only way that a part, referred to in a code description, can be condemned is either through direct testing of the part (per Factory Service Manual procedures) or, in some cases where the part cannot be completely and reliably tested, using a process of elimination.
With regard to DTC P0302, the cause of that code setting could be: lack of compression in cylinder 2, defective fuel injector, clogged EGR valves or tubes, burned valves, ignition timing that is inaccurate, vacuum leaks, low fuel or low fuel pressure, leaking head gasket, bad camshaft sensor, bad crankshaft sensor, bad mass air flow sensor, bad oxygen sensor, bad throttle position sensor, bad catalytic converter, and bad powertrain control module (rare, exceptional). There are other causes as well.
A point is the situation has to be diagnosed and no parts should be replaced unless it is certain and proven that they are actually defective. If you wish to schedule a Check Engine Light diagnostic with a certified YourMechanic specialist please follow up and the mechanic will identify the root cause of the trouble code at your own location.
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