Jeep run rough has noise from rear, hard to start

Question

Hello, we have a 1992 Jeep Chorokee 6 cylinders, engine run terible and there is a noise I have mobile mechanic look at the problem and replaced the water pump, noise is still there and the engine runs terrible mechanic can not read code he say the system is old style i cant keep putting money in this I need the vehicle for work mechanic doe not know what is the problem anyone else know what I can tell the mechanic the problem started when the noise started Jeep does not run good.

Answer 1

1992 Jeep this would be a OBD 1 system, Have the fly wheel check, if the fly wheeel  moved out of its position you would would have a noise from the rear, and on the fly wheel ( or what known as the flex plate) is the toner for the crankshaft postion sensor.Being shifted out of position would result in hard start, rough idle and a misfire condition. 

 Here a fly wheel (Flexplate) for a Jeep 4.0 attatched to it is the toner for the crankposition sensor, if the flexplat moves out of its position due to a crack you can expect noise from the rear and a misfire condition due to the CKP signal being out of position

 The signal for the CKP is on the flexplate.