2004 PT CRUISER began to idle rough, sometimes shaking the whole vehicle. It seemed like it wanted to stall, but never did. It was always worse after a car wash or during damp, or humid weather. I used carbon cleaners in the gas, took it on the turnpike, as suggested by the dealer, but it continued. After several months, the engine light came on so I took it in. They said carbon had built up in the engine and it was not covered by the warranty because it was caused by the gasoline. I have always used 87 octane (as suggested in the manual) and most of the time used 2 gas stations. When I talked to the dealer as they were repairing it, he said it is a common problem with the PT CRUISER. I only have 23,000 miles on the car. It is parked every night in a heated/cooled /dry garage. I have regular oil changes and follow the maintenance B schedule faithfully.

- North Huntingdon, PA, USA