running rough 97 cherokee

[JDusen4211]

now that i have the power windows out of the way from my other post here is yet another problem...

the 107k motor was running rough so i changed the air filter, plugs, wires, rotor and cap and it still ran the same. so i added injector cleaner and gas treatment. still ran rough. it cranks fine and imediate so i don't think that the timing is off significantly but i do hear tapping at idle, so i am going to check it with a light. it runs fine other than at idle. it doesn't seem to suck down an abnormal amount of fuel. i did notice that once or twice when i applied gas, it hesitated and then caught up... but it was so subtile that when it occured, i thought it might have just been me. the guy who owned it before me said he replaced the throttle possition sensor as well as plugs, wires, cap and rotor at 95k.

I am not sure what else to check for, any other suggestions?

[Cam7]

Try cleaning the throttle body and Iac Motor on the back of the Throttle body. Carbon can build up and cause loss of Idle and errratic Idle. Use a tooth brush and some carb cleaner or laquer thinner. Just to be on the safe side check the fuel pressure to see if you are running the right pressure. If nothing improves get a spry bottle of water and wait untill dark and spray the ignition wires. Look for any arching.

[SteveB05]

Did you happend to look at the old plugs as they came out? You may have a leaky injector which if bad enough would blacken (carbon build up) the plug.

[JDusen4211]

the plugs looked clean with no residue when they came out and all of them looked the same.

[JDusen4211]

will do and will report back. seems like it would get worse or soemthing after running for 10k,but nope... still runs the same but just not quite smooth.

Originally Posted by Cam7

Try cleaning the throttle body and Iac Motor on the back of the Throttle body. Carbon can build up and cause loss of Idle and errratic Idle. Use a tooth brush and some carb cleaner or laquer thinner. Just to be on the safe side check the fuel pressure to see if you are running the right pressure. If nothing improves get a spry bottle of water and wait untill dark and spray the ignition wires. Look for any arching.

[JDusen4211]

i replaced the IAC motor and cleaned out the throttle body. it still runs rough at idle. i think i hear the motor spark knocking as well, but i am not sure however the noise is becoming more noticable. i only hear it below 1500rpms. i was looking at other sites to try to figure it out and saw some stuff about the MAP sensor or the O2 sensor. i don't think it is the 02 sensor because it isn't putting out any abnormal exhaust smells and i am not sure what symptoms the MAP sensor would cause.