My 93 850 had the similar "jerking" problem when the volvo repair shop replaced the fuel pump after the car was stalled. I have since then replaced distributor, rotor, relay and throttle position sensor (TPS) but could not fix the problem......
Finally I found this iformation in Volvo technical service bulletion # 101 for 1993 model volvo 850. It says, electrical interference between the RPM sensor wiring and the secondary ignition system may result in a monentary intermittent jerking sensation while driving. Should this condition exist on vehicles before chassis # 068446, secure RPM sensor wiring harness to camshaft posotion (CMP) sensor connector with plastic tie strap, P/N 948211-8.
According to the instruction, I tied the RPM sensor wiring close to the CMP sensor connector with a regular plastic strap so it's not routed right next to the ignition wires and rotor. The jerking problem was solved and never happened again!
Well, seems like a another design problem for early 1993 volvo 850 model. The mechanic woking on the car might have touched the RPM sensor wiring or broke the plastic tie "fix" accidently. Your car might just be the same case.
Good Luck!
Brian G.
93-850, 90-740, 82-240, 81-240
|