Q: Spark plugs and coils on 2001 Toyota Avalon

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My engine was running rough intermittently. My mechanic told me that one bank of spark plugs and coils were bad. It was a very expensive repair. When I got the car back, it was doing the exact same thing as before. Then he "discovered" that a rather inexpensive part was opening on an intermittent basis. Was I had?
(1) Answer
sounded like he took a guess. i am surprized he gave it back to you the same way.

talk to him about the repair. plugs/coils are a maintenance item. maybe he can credit you the labor.

did he charge you for a diag or did you request the repair??