I have a 96 Jeep Grand Cherokee Laredo, 96k miles, 4.0 engine, automatic, 4wd. Last Saturday Aug. 22 it started to stumble, buck and hesitate on acceleration. Not all the time but intermittent and has been doing it since. I used the key to bring up codes on the dash and none. I put on a scan tool and no codes. It had a bad oxygen sensor, the one after the catalytic converter. Since this started 12 days ago i replaced the sensor with an OE one, removed the throttle body and completely cleaned the throttle body and idle air control motor, replaced the gas cap since the other one didn't always click and filled the tank and added 2 small bottles of Chevron Techron, absolutely on difference at all. Last year the crank sensor went bad and i also changed the grommets, elbows and hoses out of the valve cover. If it would throw a code i could narrow it down but I'm stumped. Any help, advice, directions, suggestions would be appreciated since I'm at a loss.