I have a 2007 pt cruiser we just bought it. It idles rough but drives smooth check engine light is on took to oreillys auto parts and put it on the code reader it said 1 and 3 misfire. I replaced plug

hi you might want to take the plugs back out and check the cylinders with a compression gauge and make sure you don't have low compression ...usually when it idles rough and drives good its a sign of bad valves ...the other thing is try to swap out the injectors and see if the misfire moves ...but I would check the compression first

If the valves were bad wouldnt the plugs be oily or smell of gas the old plugs looke very clean

These Chryslers are notorious for bad ecm connections, unplug ecm for five - ten mins plug back in reset MIL and drive for three drive cycles 15mins or more. Try a fuel pressure test 32psi min 28 is it will run but crappily. Coil pack may be shorted internally as well.

Will do i appreciate all the advice will relay what i do and what panned out

I have replaced coil pack with same results haven't had a chance to work on it as i am a fair weather parts changer

You didn't say how many miles are on the car....but if it is 80,000 + I would suggest changing the motor mounts and serpentine belts, as I was experiencing the same problem till they were changed. It now idles perfectly.

It shows codes 300 and 303can any one tell me what that means

Po300 is random miss fire. Po302 is miss fire on number 2 cylinder

I have the same car and I think it's possessed