Hi my car has about 19K miles on her now and she started to stumble, rough idle, and start to show her age. I surf around the web and found out that cleaning the combusion chamber helps rough idle. So I went to a Dodge dealership and bought a can of Mopar Combusion champer cleaner and use the entire can for the throttle body. I took off my entire intake system and spray directly into the throttle body, stopped when the engine is dropping RPM, and sprayed again when the idle regained. The whole process took me 10 minutes (make sure you do this outside because the a lot of smoke will come out of your exhaust). I turned off my engine and allowed it to cool for one hour and started it up again. Allow it to idle for 10-15 minutes and start to drive it really hard for 20 miles or so. A lot of smoke and it can be stinky during this process. Service engine soon light turned on but it won't last. I also filled up my gas tank and used BK 44 fuel injector cleaner. The result was amazing, my car runs very smooth and responsive now. This process really works for me so I just want to share.

 

The intake valve carbon deposits that you were removing usually build up over time. In a prior lifetime, I had a 1986 VW GTI. After ~11,000 miles, I had the problems with cold start driveability and stalling. After an engine de-carbonization procedure at the dealer, the service manager showed me a TSB that talked about the need to use gasoline that had high levels of detergents. The TSB named six companies that had been found to have the right quantity and kind of detergent in their gas. Chevron was one of the six. After switching to Chevron in all of my cars, I have never experienced deposit build-up since. TopTierGas.com is an effort to increase the availability of high quality detergents in the gasoline supply. TopTierGas.com publish a list of retailers that sell product that conforms to the TopTier specification. I imagine that if you use gas from a TopTier retailer, you will not need to do the de-carbonization procedure in the future.