On my '96 850 w/160K on it. I don't have it in my notebook...but I changed the T-belt at about 144K (when we bought it) and I am pretty sure that I changed the plugs on it then. I put in standard single-electrode plugs.

It has a miss that sure seems like it is ignition related. It misses under load and at low rpm...on at least 2 cyls.

Should I have put in Volvo 4 wire plugs?

 

I think you are fine with the standard plugs - older Volvos tend to prefer the traditional copper core plugs vs the platinum/iridiums which were designed for hotter coils. What I'd do is replace the wires/cap/rotor - you can look at the wires to check for a date code, if they are older than 4 years, time to replace. If you've never done the rotor and cap, its possible (but a PITA) to do it without removing the air box, easy to do it with the airbox out of the way. You may want to also replace the plugs since the wires will be off and check for color and correct tightening torque. If that doesn't clean it up, then I'd look into the fuel pressure...

 

Well, I pulled the plugs. They are NGK U-Groove and I thought that they were a tad bit wide....at a smidgen over .035. They should have about 15K on them.

The date code on the wires is 95-22...original wires. (my car is a 96).

Inside the rotor, in the hollow base, is a number 94, is that the year of manufacture?

The cap's contacts looked a bit corroded....and it had some oil in the bottom. I am going to clean it out and go from there.

I am going to order some stuff from Rockauto and see if the beast will run better.

 

I forgot about this.

I installed the stuff from RA.

Plugs, cap, wires and rotor. She runs like a champ

 

cool. Generally wires should be replaced every 5 years and older Volvo's tend to run best on copper core plugs. The benefit of platinum and iridium plugs is they self clean - but that requires a hotter coil than the older cars have so they cost more with no benefit.