My 2002 Porsche 911 Carrera 4 has roughly 62000 miles. Last February (2014), all the plugs were replaced at an independent shop, then within a month all the coils were replaced by a Porsche dealer. Check engine light went on last month. The car had no power - can't accelerate on highway. Bought it back to the independent shop, who said the #2 cylinder is faulty and #2 coil needs to be replaced. Then brought it back to Porsche dealer since they have 2 yrs warranty. The dealer mechanic said they ran a compression test and the #3 cylinder is faulty and the plug needs to be replaced. The independent shop and the dealer both said the work they did not do was the problem.

My question, is it likely the coil or the plug problem to cause the car to have no power? Should I trust the shop or the dealer mechanic?

Thank you.

 

Wrong forum, but I'd go to dealer. If anything happens, they'll be responsible. With an indie, it's "luck of the draw". Have you checked your MAF sensor? When they go bad, CEL comes up. Easy fix, if it's that.