I am having the same problem it seems many Sebring owners are having. My wife got this car from my parents 4 years ago and she LOVES it (little red convertible) A year ago it started going south. A brief history is: March '07, burning coolant, replaced head gasket. Sludge build up clogged oil ports and caused engine failure. May '07 replaced engine. August '07 transmission died, replaced transmission. Had a grinding/clunking sound on cold start. November '07 Replaced torque converter. Noise better but still there.

The problem that persists is that after I have run the car for about 5-7 minutes, it begins to run TERRIBLE! It chugs like it is going to die at a stop light. If I press the gas pedal with any pressure at all it missfires and sputters. I have to BABY the gas pedal to get up to speed. This happens for about another 5-10 minutes. After that, the problem is almost gone for the rest of the day. The car always runs very smooth and I never notice any missing or sputtering after that, especially at running speeds. It is also much worse on damp or cold mornings.

I get SES codes that indicate random missfires usually on 1, 4 and 5. It has also shown a 'poor efficiency' code. I have had the EGR replaced with no real difference. Throttle body springs were checked and cleaned. Plugs are good and not fouled. Wires are only 1-2 years old.

I have seen this problem with other owners and the suggestions are to look at the O2 sensor, distributor cap and rotor, distributor assembly. I am going to replace the O2 that is throwing the code but beyond that I do not want to keep hanging parts.

The odd thing is that it only happens in at initial startup and only after running for 5 minutes, then happens for about 5-10 minutes pretty much goes away. Nothing is consistent.

I would appreciate any suggestions other than what I have already seen.

 

Has the fuel filter been replaced or the fuel pump tested to see if it is delivering proper pressure? An excessively dirty filter will not allow sufficient fuel through during high demand periods such as acceleration but have sufficient fuel flow for idle or constant speed. I'd start there personally.