2.7 v6 2006 Sebring
 

Hello all. I'm not quite sure what is going on with my car so I'm asking relying on the people with experience.

Vehicle: 2006 Chrysler Sebring 2.7 v6

Problem: Idles rough and won't shift past 2nd gear (if gassed hard, it won't shift at all). Engine light is on, showing codes p0303 and p0203. After sitting for a bit, the problem will go away. It will randomly start when I first start the car, and continue till I let the car off for an hour (sometimes more).

What I did so far: At first, I thought it was the battery. I replaced the battery (it was going bad anyway). This solved the problem for a ride. I parked the car. When I got back in and started the car, the problem started up once again. I then checked the codes and saw it was a misfire in cylinder 3. I replaced the ignition coil. This solved the problem for about a week. It then randomly started again. This time, I hooked it up and found the p0303 along with the p0203. I put some injector cleaner in, hoping it was just clogged up. I drove for 30 miles and parked it. After an hour or two, I drove it again. Ran great for a day. The code keeps coming back along with the rough idle/shifting problems. I bought a new fuel injector along with intake manifold gaskets. However, if this isn't the problem, I would love to avoid that. Could it be anything else? If the fuel injector was bad, wouldn't it be a constant problem? I may have to take the intake manifold off either way to replace the thermostat housing. Is there a way to easily check the fuel injector?

Thank you in advance for any suggestions.

How old are the spark plugs?

Spark plug
 

I'm actually not sure. I just bought it a few months back. However, talking to a few people, I've been thinking it may be going bad. Could that cause the car to run perfect until shut off and started back up (then run fine after sitting for an hour)? Along with causing the p0203 code? I'm going to pull it out tonight on break from work. Thanks for taking interest.

Spark plugs looked good. I switched 3rd and 5th plug to see if the position changed on the code. Came on with same codes. Running normal and smooth. I unhooked the negative to the battery for a few to reset it. Upon turning it on, there was no check engine or problems. When I replaced the coil last week, the check engine went out and came back a while later (with the problems). I'll drive for a bit to see if it starts up again.

The problem came back finally. Only the p0203 code now. If it was the fuel injector, wouldn't the problem be constant? Seems like something electrical.

Many electrical problems (open circuit, short) will generate a specific code. Plugged fuel injector, not so much. Try a can of fuel injector cleaner. Won't hurt, doesn't cost much, might help.

the 203 is a circuit code not a performance code. If it was only a misfire then id say fuel injector cleaner yeah but because the computer sees that when it wants the injector turned on and its not doing it then an injector wire or pcm would be the issue.

I actually did try cleaner earlier. No luck. The car was acting up today after coming home from work. I disconnected the negative from the battery for 20 minutes. The engine light went off and the rough idle went away. Drove 7 hours without shutting the car off. When I got to the hotel I shut the car off and turned it back on. It turned on fine, no check engine or rough idle. After 15 minutes I got back in and pulled it around to the other side of the hotel. Still fine. Could it be a bad relay? Or would that affect all the injectors? Thanks for the responses.