1996 bucking

Hello guys I've been having issues with my mothers Jeep for the past couple of weeks. Assuming it might have been old or bad gas I had said to let it ride out and seafoamed her vehicle. Now with that being said I also replaced the plugs and cap. Yesterday afternoon she called me up and said that her check engine light came on and her car would periodically just buck or hiccup out when on the throttle. She took it to a friend of ours to pull the codes and got "missing" on the scanner. He doesn't really work with jeeps so he had limited on what to say about it. I've searched and seen people replacing O2 sensors as a result. I just wanted to know what kind of direction anyone could lead me in i'll be working on it this week.

It is a 1996 Cherokee with 145k on the Odometer.

Drive it to warm it up well.
Shut the engine off but don't remove the key.
Turn the key to 'ON' (last click before the starter turns over)
Turn the key to 'OFF'
Turn the key to 'ON'
Turn the key to 'OFF'
Turn the key to 'ON'
Wait a few seconds
The Check Engine Light will begin to flash a series of codes in pairs. The first set of blinks will be 'tens' and the second will be ones. There will be a longer pause, at which point it will blink out the next number, etc.

Eventually you'll get a 'five' 'five' (55) code, which means it has shown you all the codes. Search in here or post the results and we'll translate.

Jim www.yuccaman.com