Hi, my 2004 Pt Cruiser has recently been idling rough sometimes. It has about 65k miles and is in really good condition and drives really nice too. It shows no other signs of problems really, but it does have a code for a small evap leak(P0456) but that isn't a problem to me. I've been looking everywhere to try to figure out where to even start but have no clue. It also only does this when I drive on the highway for 30+ minutes. If someone could please give me some advice that would be great. Thanks

 

It may be time for a tune-up. The oem copper spark plugs are good for 30k miles; only champion/ngk copper plugs are recommended. The spark plug wires should be replaced every 60k miles. I also dump a bottle of techron into the gas tank when I replace the plugs as it seems to keep the motor 'happy'. Not certain when the plug spec and gap was changed but the plugs I use are champion 443 gapped at .040 in.

 

Thanks for your help. I was thinking it was probably spark plugs but that really confirms my suspicions. I got the car just recently so I don't really know if they've been replaced but i doubt it. I havent really had time to change the plugs and wires but ill update you on it when i do

 

I finally got to putting in new spark plugs and wires and theyre it still occasionally idles rough. It has only done it once or twice since i changed them but, is it something I should even worry about? And what else could it be? The coil pack? Thanks

 

I just replaced the plugs and wires the other day and made sure to clean the intake manifold gaskets off and now it doesn't ever really idle rough anymore but it has misfired 3 times since I did everything when idling. Keep in mind these are three different days over a 4 day period. It used to due it pretty much every time it idled. Is this something I should even care about at this point or should I just live with it? Thanks

 

If anyone was wondering my problem is completely fixed now. It turns out that the fuse for the ac compressor(idk which one it is but oh well) was corroded and wouldn't get enough power sometimes when idling and the ac compressor would shut off and cause the misfire. I genuinely don't think it makes that much sense but that was the problem incase anyone else has this weird problem.
Nevermind it isn't fixed