I have written in over the past 3 years seeking advice for an annoying problem with my 94 940. Whenever the cooler weather makes its way into Texas, I would have a problem cranking the car. Once started, it ran well. I won't go into the embarrasing list of electrical and fuel-related items I changed in the effort to correct the problem. Recently, while travelling in a rural area and trying to pick up an AM station some 100 miles away, I thought there was an unnecessarily large amount of engine-related static. On the suspicion that this was related to my wires, I ordered a new set. I thought it might be good to replace the plugs as well so ordered a new set. On replacing the plugs, I noted that the rear-most plug had obvious tip damage and erosion, unlike the other 3. Turns out after 3 years of trying all sorts of things, it was something simple that fixed the problem. I had been lax in changing the plugs. When I purchased the car used at 94K, I installed new ones. These were pulled at 160K but the problem had evidently occured much earlier. These were NGK Platinum plugs.

Moral: Check your plugs more frequently than I did for wear, corrosion, and gap clearance. Change at the frequency suggested by the owners manual. It could save a lot of frustration and unnecessary parts replacement looking for this problem.