2005 GTP hasitation when accelerating

[roman1978]

I just bought this 2005 GTP with 100k miles on it. I notice sometimes there is a hesitation under normal acceleration it does not happen all the times. Also a hear a an exhaust rattle. Could it be a bad Catalytic Converter or something else. No Check Engine Light is on. On these cars What is the warranty for a Catalytic converter?

[BNaylor]

One issue for '04 and up GPs with the SIII 3800 engine is the electronic throttle body which is associated with the "drive by wire" throttle system. You can try cleaning the inside of the throttle body with throttle body spray cleaner. Also, a basic tune up may help. Spark plugs, ignition wires, air filter, etc. There is no external owner replaceable fuel filter so forget about that.

On the exhaust rattle try to pinpoint the source. Also, make sure the exhaust system is connected to the rubber hangers or none worked off.

[roman1978]

I have replaced Catalytic converter with an 02 Sensor and now i am getting a missfire code.
The car has 100k on it should i do a tune up first or is there something else that causing this missfire. I know if you have a bad vire or spark plug it will missfire all the time. This happens randomely. There was a guy hear on the forum that had simular problem he said he replaced a pcv valve with a rubber and that fixed the problem. Any suggestions?