Still having problems with a miss at idle and stumble upon acceleration. Replaced fuel filter and plugs with no improvement. Car has recent: O2 sensor, dist. cap, crank position sensor, throttle-body and flame-trap clean. Only plug wires and rotor unchanged.

CEL codes: P0300, P0301, P0302, P0304, P0305, AND P1310.

Help!

Just a thought. When you replaced the cap, is the CPS wiring routed away from the plug wires? They may NOT touch each other. The CPS wires need to go under the cap area.

Is the MAF wiring and plug in good shape? Re-check the other electrical connections around the throttle body.

Klaus
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Common sense trumps a PhD

Klaus:

I checked all the connectors, and they look fine.

What are CPS wires?

Also pulled the injectors to check for sealing, and tightened the intake manifold. Still misses @ idle.

I gave up, so it's at the local indy Volvo shop now.

CPS = cam position sensor, the wires go past the distributer and may not be near any of the plug wires because of electric charges giving false readings.

I am surprised you replaced the cap and not the rotor also. Usually the rotor gives out before the cap.

Klaus
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Common sense trumps a PhD

Klaus-

Local Volvo shop said the rotor was the issue, and replaced same. They said that rotors can look ok, but have too much internal resistance.

Hopefully, this will cure the problem.

I've never heard of checking brake rotors with an ohmmeter before ;)
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1998 V70 AWD Turbo 190k+

Uh, ignition rotor, not brake rotor. The last one I pulled of a high mileage car was pitted quite badly. I can imagine a new cap with clean contacts might not fire cleanly with a severely worn rotor.

Klaus
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Common sense trumps a PhD

The problems seems to be fixed. It hasn't missed a beat since the rotor was replaced. The guys @ the repair shop were kidding me about "not finishing the job".....

A new cap and rotor go together, always. Even when the rotor comes with 2 allen screws :)

Klaus
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Common sense trumps a PhD

hahaha joke's on me I guess.

I have to learn to read the whole thread before cracking the joke :D

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1998 V70 AWD Turbo 190k+

I have a turbo wagon, same yr. I have the same issue - tried replacing plugs/wires, no success. Next is cap and rotor. I'll post to see what happens.
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'96 855 Wagon, 200k (and formerly 97 850, 120k)

I had the same problem ,missing at idle stumble on acceleration,replaced maf,plugs,wires,cap and rotor,coil,still ran poorly,since it stumbled off idle i figured it might be the throttle position sensor. I removed it and cleaned it with brake cleaner and it bruns great now,Im not taking any chances so I ordered a new one.I also noticed a drop of oil on the throttle plate shaft when I removed the tps ,so I cleaned the throttle body also hope this helps