I need some help. 1993 Cherokee 4.0 157,000 miles will not idle. New fuel pump, new filter, new fuel pump relay, new distributor, new wires, new plugs, new injectors, new battery, new starter. Yes everything is brand new. It will start when you hold the throttle all the way down but it spits and sputters. When you let the throttle off and it dies. And yes I have the timing correct. #1 cylinder at TDC on compression stroke and rotor pointing at #1 plug wire on distributor cap. Ive reset the computer by touching the pos and neg cables together for about an hour with the head lights on. I am lost any help would be appreciated.

 

Ever clean the throttle body and IAC (idle air control)?
http://cruiser54.com/?p=60

 

Did this start happening after battery was changed out?

 

No I got a new battery after all this.

 

yes. New IAC throttle body is clean. TPS is good also

 

The IAC body being clean does not mean the stepper motor (servomotor) driving the plunger is working properly. Or, built-up dirt around the plunger has seized it in place and that dirt cannot be seen. This same problem occurred on my 98 and the resolution was a new IAC. Concurrent with the failed IAC was a failed front O2 sensor (double whammy). Once I got the new IAC the engine began cold-idling fine but as it got to operating temp the bad O2 sensor caused much stumbling. Normal cold and hot idling came only after replacing both the IAC & the front O2 sensor.