Thanks for the help on the previous question! The same Cherokee that I asked about previously has a rough idle all the time no matter the temperature. It has idled rough since my grandpa owned it. It usually has no problems taking off. It is smooth as butter while driving, but always idles rough when sitting. Sometimes it goes as low as 300 RPM to the point where the lights dim. I have changed the spark plugs already. My grandpa had the coil pack changed and had it checked by multiple mechanics all of who couldn't find what was wrong with it. Recently, it has gotten cold in NC, and I discovered that when I start it, it idles so poor to the point where it wants to cut off (and sometimes it does). Usually when that happens, I'll hold the throttle down enough to keep it going until it warms up and then it idles at its normal roughness but not rough enough to cut off. Also, every once in a while it throws two codes: the first is a misfire in cylinder 3 and the other is for a small EVAP leak. These codes come on and go away at the same time. Lastly, it will misfire terribly every once in a while to the point where I have no acceleration when I first start the car. Usually taking off will fix this issue, but there have been times where it kept misfiring for a while after starting and moving the vehicle.
Well that's fine on number three if it has ignition coil air change it if it is a fuel injector change it then if that doesn't fix it you're in deep trouble cuz either the head gasket is blowing a number three or it's got bad valve springs or piston rings which you can do a wet and dry compression test to see if those are worn or pay acompression test to see if those are worn or pay a mechanic who knows how to do those tests
