My Jeep has been idling really rough recently. I've had issues with a rough idle since I bought the thing, and they keep going away and coming back. Here's a list of what I've replaced so far:
Spark Plugs
Cap
Rotor
Wires
Distributor
MAP Sensor
TPS
Fuel Filter

I also cleaned the throttle body pretty well too. I'm kinda stumped as to what this could be. My fuel pump is buzzing pretty loud and as far as I know that's an indication it's about to die. Could the Fuel Pump be causing the problem? It's a '96 with the 4.0 and 154,500 miles on it. Any help is appreciated.

 

Could you be more descriptive of the rough idle. Throw some RPM numbers in there. Does it kill over.

Did you clean your idler stepper motor (IAC).

 

Vacuum lines?
Fuel pressure readings?

 

Don't just throw parts at it. That gets really expensive.

Is the Check Engine Light (CEL) on? What error codes are you getting?

 

I'm getting a random misfire code. This only happens below 950RPM. It seems to me that the warmer the vehicle gets, the smoother it runs, but it's not too big of a difference. Stryker, I did not clean the IAC, where exactly is it? I don't know if it has any vac leaks or what the fuel pressure is because I don't have the tools to check them. I'll see if I can have a friend help me out with that.