2002 sebring Cylinder 4 misfire (P0304)

Maintenance/Repairs
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I bought a 2002 Sebring back in February. It had low miles and was in excellent condition for it’s age. It ran great at first but now sometimes while driving my radio will lose power. Then the brake and battery light flash. Most of the time it won’t cut off as long as I keep the rpms up. It really only dies out if im going really slow or stopped. (When it just cuts off on me like that usually it wont do anything when you try to restart it. Sometimes it will fire right back up.) After a quick jump its usually good to go for a little while. Lately when I go out to crank it after its been parked, especially if its been sitting for a day or so, it wont start without being jumped.
Constant: The service engine soon light stays on. Frequently: it idles rough, running the ac or charging my phone cause it to lose power and my headlights flicker.

I have had the alternator and battery checked multiple times and both were fine at first but the last time they told me my battery was at 46% and my terminals are a little corroded but the alternator was good. So I had it hooked up to an OBD and it gave me a P0304 (cylinder 4 misfire). I know very little about cars but, I’ve read a little about it and I know all of the possible causes. It seems kind of like a guessing game I dont really want to play.

Knowledge or Experience;
What is a good starting point? Is there a most likely or most common cause? What part(s) should I replace first? Advice please & thank you!

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“terminals are a little corroded” That could be the problem. Why didn’t you get this fixed? Take the connections apart, clean inside and outside. Also do the same with the other end of the heavy cables, one to ground the other to your starter. Once you get that fixed, you can look again at a possibly bad battery.

Do you know how old the battery is? I’d just replace it proactively. Remember each time the battery is totally discharged, it suffers some damage. Do that enough times and the battery needs to be replaced. From your question, you have had to jump the car many times, so I’d say the battery is bad now.

Once your electrical system is good, you can look at the misfire problem. Is the check engine light on? blinking?

One caveat, if the light is blinking, don’t drive it, you may cause other damage…

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