My 940 misfires on acceleration and even at idle when cold. As the car warms up, the idle settles down, but the serious misfiring continues on acceleration. When cruising all is well. But as soon as I try to give it some gas it misfires. This continues for about forty minutes, long after the car has warmed to operating temperature..

And then? It ceases its misfiring and runs as well as it ever has run, smoothly going up through the gear changes [it is an automatic transmission] and in general acting like its old self.

I checked the distributor cap for oil and did find a little on the rim which I cleaned off. The cap is not a new one and the rotor looked a little rough around the contact edge when I removed it and looked at its condition. I cleaned up the rotor contact edge and did a little sanding at the contact points of the cap but when I took the car out later it returned to its misfiring.

Anybody else experienced this?

Bob

if you look on the swedishautoparts website.. they have an answer for this problem.. i saw it..
i cannot remember there is a part that will fix it.. check vacuum hoses any hoses for leaks etc

1. failing coil
2. failing plug wire/s

would be where i start looking

Right on. I decided to have a look at the plugs and when I pulled on the wires, two of them broke rather than pull out. I replaced the wires and all is now well again. Thanks to all who contributed to this result. Much appreciated.

Bob

Good for you

After a lot of work on my 940 (replacing a leaking fuel filter, rotten exhaust and cat, etc) I have an off-idle stumble and occasional misfire to track down and I betting it is a bad plug or wire.

Add to this a loose plug or plug nipple.

Thanks. I will see what I can do about checking the coil and wires as well as the plug and plug nipple.

I forgot to mention that the flame trap holder's small nipple is broken off and this is leaving a vacuum leak as a potential problem as well [connects the flame trap to the intake manifold through a short hose]. I have ordered in a new flame trap so should be able to remove that one as a potential culprit very soon.

I do have a coil on my 82 242 and could give it a try in the 95 I guess. If it works it would let me know if the coil is failing.

Thank you all.

Bob