2003 PT Cruiser

I have a PT Cruiser with over 200000 miles on it. In the past month, the check engine light came on, and at around 2500rpm it starts to buck, so I shift into the next gear. Two or three times it has taken a lot to start the car. It is not a constant problem. If it’s raining, the light goes off and I have no trouble. If I sit in the driveway and rev the engine up to 3000rpm or more, I have no trouble. If the light is off, the car makes a kind of whistling noise. I had the code checked, and replaced the cam position sensor, but the code still comes up, and the problem persists.

Any suggestions?

[i]  I had the code checked, and replaced the cam position sensor[/i]  

There is no code that says replace the cam positioned. There is (I believe) a code that says the computer is getting an unexpected error code related to the cam position sensor.  

Can you get the actual code.  It likely will be in the format [P1234] Don't bother with any English translation of what that might mean. 

Auto or manual transmission? 
When was the transmission fluid last changed?  
When was the last time the spark plugs and wires replaced? 
When was the fuel filter last replaced?

Sorry, I didn’t mention, the code was P0340, it’s a manual transmission, I changed the plugs/wires last July. It has been a long time since the transmission fluid and fuel filter were replaced. (I can’t remember).

Turbo ?
CSA

2.4L Engine ? Has The PCM (Power Train Control) Module Ever Been Erased And Reprogrammed With New Software As Per The Chrysler TSB (Technical Service Bulletin).

Starting:
That would probably take care of the starting problem. I’d check with Chrysler and describe your symptoms (code PO340 pertains to this) and have them check the TSB that covers 2003 models with the 2.4L engine.

Starting and / or Bucking:
2003 & 2004 models with a naturally aspirated (non-turbo) 2.4L engine had problems with spark plug carbon fouling. A TSB indicates the new plugs that are now specified for this vehicle. The plug wires are to be changed with the revised plugs, for the first installation of those plugs to prevent possible high secondary ignition voltage flashover, caused by a thermal set of wires to the old style plugs.

What did the old spark plugs look like ?

CSA

Non-turbo engine. I bought the car used in 2005, if the TSB came out before that, yes it was done. If not, no I have not had that done.
When I changed the plugs, they were pretty bad. I purchased over the counter plugs and wires at Schucks/O’Reilly auto parts. They only had one series available.