1996 850 - P0300 & P0302 + flashing CEL

[SonicAdventure]

Thanks Erik. I am in the process of ordering a complete tune up kit from FCP: new Bosch cap and rotor, new BG plug wires and new Volvo spark plugs. The cap and rotor from my 1998 are pretty much just as bad so no reusing them.

With the old BG wires its still starting rough but idling fine now, but as soon as a load it put on it at like 35-40 MPH or up, it stumbles and fumbles. Now that I've looked at all the parts and even with no clue how old the plugs look I can see why. With this car only having 73,000 miles I would not doubt the cap and rotor currently on the car are original to the car, so its about time. The cap is really full of carbon fouling and cracking / heat distortion and it just looks old.

[greg850r]

I've seen plug wires that idled fine but caused problems under load. I also had a bosch rotor that did the same thing. I think you're on the right track replacing them. Rotor, cap, wires, plugs will likely cure it.