Im trying to get my sisters jeep running better. It is a 91 Cherokee with a straight6. It sputters and misses and has no power and bucks like crazy from 30 to 55mph. It seems to do this when it is shifting from 2nd to 3rd and into overdrive. The speedometer doesnt work half the time and the cruise control quit working. Does this sound like a speed sensor on the tranny could be bad?

 

What's the fuel pressure is psi? When was the last time the ignition system was replaced?

 

I would check all grounds first.