My 94 Cherokee w/ 230,000 miles is experiencing a rough idle. It almost sounds like mini backfires. I expecially notice the problem when the vehicle is in reverse backing up. Once you press the gas the problem disappears. The problem is constant and only noticable while idling. I have replaced:

Alternator
Idle Air Control Sensor
Wires & Plugs
Rotor & Cap
Throttle Position Sensor
Cam Shaft Position Sensor
Fuel Pump
Ignition Coil
Battery
Fuel Filter
O2 sensor

I have used injector cleaner. The throttle body is clean. Checked for vacuum leaks.

I am running out of ideas, money, and parts to replace. I suspect the problem is related to a sensor but I have yet to figure out which one. Any advice you can give is appreciated. I have seen this problem mentioned in multiple other threads but have not seen a definitive fix.

 

Any codes out of your OBD?

Pull the coolant temperature sensor(CTS)out of the thermostat housing. Polish the probe(3M pad or the like)until it's shiney brass. It to sends a signal via the PCM to your IAC. If it doesn't help you can do an ohms test to find out if it's bad.

 

map sensor my 96 doesent have an egr valve if that year does check it theres really a million things it can be i just fixed hat problem on mine it was the o2

 

There are no codes or engine lights.

 

Go to your parts store and get them to test your battery(w/o load and w/load),alternator,starter,charging system,and scan for codes. It's all free.