Intermittent rough idle?
2001 Chrysler PT Cruiser, have had it for about 6 years and for the past 3 or 4 years of owning it, I've been dealing with an intermittent issue of the car idling very roughly and nearly stalling. It seems to come and go without any clear cause—sometimes it will develop a rough idle out of nowhere and then it'll disappear for months. When it's having a rough episode, the engine is only rough at idle and will smooth out when I give it gas. I've replaced the PCV Valve, replaced the main intake hose on the air filter, cleaned the IAC Valve, and cleaned the throttle plate in the throttle body but I'm still having this issue crop up from time to time. It gave me a pretty bad episode a few days ago and it's got me concerned about trying to get to the bottom of this because I'm tired of driving my car and worrying about when it's going to have another rough idling episode. I replaced the PCV value just now and during my test drive I did notice a very slight miss/unevenness during idling, but not nearly as rough as it was during the episode it had a few days ago. The only codes I have are P1684 and P0601—the car has given those codes well before this issue started happening but I'll throw those out there in case it helps with diagnosis.