2002 Concorde LXI Problems AGAIN

I have an 02 Concordde LXI. In an earlier post, I metioned that I had to change the PCM. It was idling rough, missing. Last week, the engine light came on again. Took it to the dealer, they said the plugs needed changed and the injection system needed cleaned out. Had it done and it was fine for a few days. Today, did a little running around and the check engine light came on again. Same problems again. Any suggestions on where to look or to have the dealer look?
 
All I know is that this is gettig old. I have made only one payment and repairs have been 3x the monthly payment.
 
Thanks

whats the code  that will help

On my $70 code reader I am getting P0300, and P0300 with what looks like a p and d. I am also getting codes for misfire, o2 sensor, catlyst, fuel, comp, and evap. These are the sme codes when I took it in and the PCm needed changed. The last time I took it in, I had the exact same codes and the mechnaic siad it was the plugs and fuel injection.
Thanks.

give me all of the p codes

The P0300 codes are the only codes. The manual says that it is random, multiple cylinder misfires.

U said  I am also getting codes for misfire, o2 sensor, catlyst, fuel, comp, and evap. whats the deal???  What u need is to find out which ones are missing  and go from there  that u will need more then a $70 OBD2 scanner.  With out more info  u are pissing into the wind and just guessing. I will tell u from all my schooling and 11 years of working on chryslers the pcm is the last thing that should be replaced  not first.

I did say that about the other codes. That is also why I took it to the Chrysler mech. All of these computer chips and codes are new to me. I'd rather deal with an older (pre 85) American car with a 4 barrel carb, headers, etc.
But I do like my Concorde and want it fixed. The mech should call later today and tell me what they found. Hope it is something stupid and cheap.

I got my car back from the dealer this last weekend and the mech said that the code they had was a one time fluke. They reset the the computer and they were not able to get the check engine light to trip. They drove it around at low speed, highway speed and in between and could not get the light to go off. Been using it all week and no issues.

Check your gas cap, had the same problem,just a loose gas cap!

gap cap will not cause a misfire 2 different systems