My 940 (94 non turbo) has always been a great car. I only encounter problems after heavy rains. Car will take a longer than usual time to start. When started car idles rough, stutters and dies out. I can not understand this problem. I have to put in nutral from preventing the car from stalling out. When I press on the gas pedal it stutters and stalls out. The issue only seems to go away after the car really warms up or later on during the day when the sun is out.

Car has been well tuned and MAF sensor replaced, fuel relay and fuel pump replaced at tune up. Car has 138k miles.Any feed back would help out allot thanks...

 

Probably dampness on the ignition system. I have even seen it inside the distributor.

As a quick fix spray the cap and plug leads with WD40. As a longer term fix remove the cap and leads, dry thoroughly with a hair dryer and spray the outside of the cap and the leads with Dampstart.

 

i had exactly the same problem and found it, still trying to come up with a "perfect" fix though...

look here: https://volvoforums.com/m_42500/tm.htm