Kevin1 wrote:The dealership had all kinds of excuses for the misdiagnosis ... he kept trying to explain how these "computer controlled transmissions" will act up and shift wrong if a plug misfires (?!?!) making it hard to fix.
This is believable. Ignition faults can masquerade as fuel or driveline faults. Wife's car threw fuel delivery codes at the dealer. Before commiting to extensive and expensive repairs, I searched the car forum and found several reports of coil-on-plug failures
producing the same codes. Like you, I replaced all coils and plugs, and the problem disappeared. All parts, including the scanner, were less money than his (erroneous) estimate.
I doubt they drove it or even plugged it into their scanner.
This is where the dealerships failed Mark, you, and I. There's no excuse for not performing an OBD scan. My cheap Harbor Freight one has diagnosed both our modern cars; the ones dealers and repair shops use have much more sophistication. The best tool won't work unless you use it.