My car is backfiring

2007 CHRYSLER 300
150,000 MILES • 2.7L • 6 CYL • 4WD
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NORMA ELISA WILLIAMS-COLON
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I had put too much oil in it. the next day my brother drain the oil and put new spark plugs and backfire. now you change the coils it still backfiring. I need to know what is wrong with my car? I paid $75.00 to get it fixed and it is not fixed. we put two fuel injectors in there and it still shaking. what is the problem?
Oct 1, 2017 at 2:19 AM
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HARRY P
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Sounds like he probably got the wires crossed on two of the coils. IE: he plugged cylinder four's coil into cylinder two's wiring, and cylinder two's coil into cylinder four's wiring, or something like that. I would say get a scanner on it and see which cylinders it says are misfiring, and then switch their wiring and see if it is better. If you cannot get a scanner, then you will have to do it by trial and error. Basically you would switch two cylinders around and see if it got better. If not, then you switch them back and try another combination. Keep doing this until it is right.
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Oct 1, 2017 at 4:43 AM