I have a 2008 chrysler 300 2.7 Changed spark plugs on car. After i put it back together and started the car up, it started to backfire under the hood. I thought maybe it could need new ignition coils now that spark plugs were new. So i changed all 6. Its still back firing. What could have caused it to back fire and how can i resolve it. It wasn't back firing before i changed anything on it. Please help.
My car has 197000 miles.
My car has an automatic transmission.
Hello it sounds like perhaps one or more plug wires were not re-attached in the correct order. This is especially easy to do on an engine like yours that still has plug wires routed all over the engine. The firing order, which should be on a label somewhere under the hood is: 1-2-3-4-5-6 (believe it or not), and #1 cylinder is the front cylinder, passenger side of the engine. For assistance with this problem, I recommend a backfiring inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, and give you an accurate assessment of damage and cost estimate for repairs.
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