I have a 1994 jeep Cherokee sport 4.0L 6CYL. with 214,000 miles. It sat for over 6 months last time it stopped running. Have had it running for about 3 months now. when I first start it, I take of and it bog's down for a second and then takes off. it gets better as it warms up but it does happen every time I come to a stop and take off again. My gas mileage is also down to about 60 miles a tank. went from 280-290 range to 220-230 range. I have replaced the Plugs and wires, the Distributor, Crankshaft position sensor and had the timing done. That got me up and running again. Since then I have changed oil, air filter, vacuum hoses, Throttle position sensor, both front and back ccv elbows and grommets. put in a new battery, new starter, replaced inline fuel filter and put sea foam in the gas tank a couple times. Pulled the plugs out couple weeks ago everything looked clean and gapped right.It runs great once I'm going just poor gas mileage. The Oxygen Sensor is next, and then idle air sensor. Any other suggestions someone else might have would be appreciated. thank you

 

sounds like my problem which i haven't figured out yet. THIS IS JUST A SUGGESTION...try replacing the fuel filter by the back of gas tank, and replace the fuel pump.

 

Don't do the IAC valve unless it's a high idle issue. Do both o2 sensors and don't skimp on quality. I dropped like 110/ea on my 99's.. (don't say I paid too much. My budget, my xj, and my being really, really sick of my hesitation issue...) umm, anyways, have you done a pressure test at the fuel rail, or plugged into a code reader, etc?

 

A couple more things to check- the PCM, unfortunately a thorough check of this is costly.. And as afore mentioned, drop the tank and inspect the pump/filter assembly.

 

I have changed the filter by the tank already. I went to the auto parts store the borrowed there computer reader and had nothing show up when it I read it. O2 sensor is hopefully the answer. Thanks for the help will post if this does the trick

 

Good luck man!

 

try replacing both 02 sensors
1. precat
2. aftercat

GOOD LUCK; keep us posted

 

have you pulled the fuel rail off and soaked the injectors, sounds almost like a fuel delivery issue to me. I would start with a deep cleaning of your injectors.

 

Are you getting a CEL?

 

check fuel pressure?

 

can we get this to oem tech and more response?