I have a '97 Volvo 850 non turbo and I am having an issue I can't figure out. I have changed many parts in the last 2 years since I bought it. Plugs, rotor, cap, wires coil, EVAP stuff, cam sensor, air pump and valve for the exhaust manifold, and the car has been trouble free. A few weeks ago it got a bad misfire, so I changed the plugs, cap and rotor. No joy, so I changed the wires again, this time with Bougicord. Still, runs like crap. Changed the MAF sensor, even though I got no MAF code, nothing. Changed the intake hose, flame trap and vacuum tree. Nothing The only code I am getting is secondary air pump so I must have a bad relay. I will change the coil today to rule that out. Any ideas? Oh I filled up the tank and put in a bottle of fuel injector cleaner.

 

When does it run bad? All the time, accelerating, cruize, load???

Have you done a compression test? Lots of burnt valves out there.

 

Thanks for the reply Boxpin. It would start up fine and start to misfire after like 30 seconds. I replaced the ignition coil today and now it runs like a brand new car. Lesson learned, don't use made in china parts. Use OEM.

 

Good to hear.