Replacing O2 sensor in 2006 PT Cruiser

[appletek]

Hi All,

I apologize for jumping in late.
I'm new to the forum.
I have a 2006 Touring Ed. and at 37K an idiot light came on. The dealer had to replace the O2 sensor. (and my average mileage immediately shot up to 23.7 mpg from 19!)
Kind of unrelated, but also a surprise, the engine started to idle rough and kept stumbling while driving. It seemed like it would stall.
Took it back to the dealer and they found a PCV valve stuck open and oil in the intake runners.
Runs much better now.

[Cartman]

it was probably fouled out due tot he oil the engine was burning. that happens more than you think. same goes for worn spark plugs and all that unburned gas that goes intot he exhaust.