Engine Performance problem
1998 Volvo V90 6 cyl Two Wheel Drive Automatic 208000 miles
For some time, the car is ahrd to start. If I push on the accelerator normally, the engine acts like it wants to stall. If I push on it very slowly, it will acclerate. After about 20 minutes, the engine starts to run rough. If I turn the car off at this point, it will not crank until it has cooled off completely, several hours. I have a code reader which shows live data. It says that the rear heated O2 is faulty. I replaced it and the scanner says that it is still faulty (bad ECM?). The scanner shows the timing is 9 degrees advanced. It is a distributorless ignition, the ECM controls the timing. After the warm-up, the timing starts to jump sometimes to 12 then back to 8 or 9, then maybe to 15 and back to 8 or 9.
Sunday, April 4th, 2010 AT 11:06 AM