96 850 turbo 140,000 miles

I keep getting misfire codes, but I feel no misfire. I mostly get a code for cyl #5 misfire. The car has new Volvo brand spark plugs, plug wires, cap, and rotor. Freeze frame data on the codes always indicates that it happens at 840 RPM. It mostly occurs at startup. The check engine light shuts off after a few miles of driving, but it comes back on at random during startup.

The car is stock except for an MBC set at 12psi, but the problem has been occurring long before the MBC was ever added. The car runs great so Im not too concerned, but the check engine light annoys me when its on.

 

You might have an injector bleeding down causing the misfire. In other words bad injector.

 

I was going to suggest a faulty coil since it only seems to happen at a specific RPM, but a faulty injector sounds more logical since it is only occuring on one cylinder. If you can, swap the plug wire from one plug to another just to see if it is a plug wire.

 

Thats what I was thinking but I was hoping no one would agree with me. I cant imagine how much Volvo is going to ask for an injector.

Would it be worth it to do an injector bleed down test?

I don't think a plug wire is to blame because it did this before I changed the wires. The car had original plug wires and dist. cap, so I was hoping that replacing those parts would fix it.

 

You can pull the fuel rail and see if it is leaking.
The Dealer will only sell as a set last I knew.

 

How about swapping the #5 cylinder to #4? If the code moves to #4, case closed.