My 93 940 has about 232,000 miles on it. Most maintenance is current. Recently the idle has been very rough, a little smoother in neutral. It doesn't hesitate or stall and acceleration is fine; excellent as always.
I've replaced all the spark plugs, but one of them [No. 2 or 3] was hard to remove. it had evidence of anti-seize. I didn't cross thread it, but it went in with the same tension, so maybe it isn't seated properly [I don't have a torque wrench.] Should I use a torque wrench on this plug? Wires are seated properly.
I replaced the air filter, and flame trap, and use an occasional fuel injector cleaner. New shocks. Could it be the engine mounts [original] or distributor cap and rotor? [replaced at 175,000 miles] or spark plug wires [replaced at 180,000 miles] Also have a new fuel pump [another story]
I look forward to some advice/comments. I have new belts, which I hope to get the courage to replace soon.
Hohenstauffen