Why would your 1989 Crown Victoria 5.8 V8 sometimes jerk at weird speeds?

Answer 1

I would suggest checking or replacing the catalytic converters. Even with single exhaust, you should still have two -- one from each side of the engine. Anyway, when they get old or bad or clogged, they car becomes "constipated" and it can't expel the exhaust and the whole car jerks. Depending on how badly clogged the converters are, the amount of jerking will vary. You will also notice the jerking is intermittent -- there will be more jerking at higher RPMs because there will be more exhaust trying to escape due to higher output. Replace both catalytic converters and the problem should be gone. This happened to me, so I'm speaking from experience. **NOTE: if you're nearing the time to renew your car's registration, take it to have the emissions inspected before you replace the converters. Since your car is basically contipated, your emissions output will be low since most of the waste is being kept in the engine and exhaust system rather than being expelled out the tail pipe into the air. You might also have the transmission checked... I have a '94 and it will downshift a lot of times for no apparent reason whatsoever. I know it's the transmission I'm not certain exactly what the problem is though. My trany shuttered on my 1995 vicky, and then my check engine light came on. When it was put on a computer, it showed a "bad shift solonoid". It is mounted on the outside of the transmission. I would have that checked for any shifting problems. My P71 did this and I had the MAF Sensor replaced. It fixed the problem right away. My jerking problem had nothing to do with the tranny. Mine would jerk and sometimes felt like it down shifted. I would go with the MAF Sensor.