Paul's 1987 Volvo 780

I recently purchased this car from my brother-in-law. It belonged to his father who passed away recently. I drove the car from Florida to Maine. In Viginia I almost ran out of gas (the gas gage was not working…now it does). After I gased up and started the car I noticed that at idle the engine would rev up slightly and then idle down and then repeat the cycle. I don’t know if almost running out of gas has anything to do with the car’s current problem. During acceleration and at highway speed the car seemed to run fine, but continued to exhibit the weird idle behavior. After getting the car to Maine I drove the car locally for about a week and then it quit on me. I could get it started but it ran very rough and then it quit for good. I’m getting fuel to the engine and also spark. The spark, however, seems weak and the plugs are fouled.



Have any ideas, anyone.

The older Volvos can run rich from a bad engine coolant temperature sensor (CTS) …The one which feeds the engine computer; NOT, the one which feeds the dash temperature gage. The CTS won’t set an check engine light. Change the CTS and spark plugs.

Thanks for the advice…but would that cause the car from not starting? Also, they made only a little over 8000 of these Italian build Volvos…are there any service manuals for this model? I can’t find anything on line.

Thanks for the advice…but would that cause the car from not starting? Also, they made only a little over 8000 of these Italian build Volvos…are there any service manuals for this model? I can’t find anything on line.

Yes. Seen it. Cured it with a new cts sensor. Somestimes, there’s is no after-market manual available. Case in point: there is no Hayes, or Chilton’s, for a 1982 Mercury Cougar. Go figure.