Hello All,

I have a 1996 850 GLT wagon with a 5 speed manual, non-turbo with 375,000 on the odometer. Recently the “Check Engine” light came on. Before it did, I had just started up my car and the engine was warm because it had just been driven. Once I started the car, I noticed the idle was rough and thought I sensed a “misfire” in one of the cylinders. The afar a few seconds, the “Check Engine” light came on. I noticed that the RPM level was slightly elevated. Normally with the engine warm, it sits at between 800 RPM to 1,000 RPM. Now it was at 1,200 to 1,300 RPM.


I brought my car with the CEL on to my private mechanic, and he attached a scanner that indicated all cylinders were misfiring. He believes the problem could be a fuel pump relay or the fuel pump itself could be failing. However, he does not want to replace them unless he is absolutely sure. He cleared the CEL and then drove the car and it ran perfectly. Both O2 sensors were fine. The spark plugs are replaced ever 30,000 miles with Volvo plugs and the spark plug wires are replaced every 60,000 miles. Currently the car has 15,000 miles on the spark plugs.

The CEL came on again, so I will be bringing my car back. I picked up the car at the garage when the engine was stone cold. When I started it, it ran fine. About 2 miles later when I came to a stop light, I could sense the car’s idle was slightly rough, and within seconds the CEL was triggered again. I noticed that again the RPM level is elevated (1,200 to 1,300 RPM). My mechanic told me the CEL only tells him the cylinders are misfiring, it doesn’t tell him the cause. Again because all the cylinders are affected he believes it could be a fuel pump relay or the fuel pump. The cylinders are not getting enough gas, so that is what is causing the misfires.

Does anybody have an other theories as to what is causing this problem and how to fix it? Thanks in advance to all who respond.


Hugh