yeah, i agree with joe, it has to be in the spark system somewhere. ur truck has a distributor cap and rotor? i had an issue with mine where i went to start my mazda up and it wouldnt turn over, just sat there, and it tried to start but wouldnt, turned out my coil wire (BRAND NEW) came disconnected from the my distributor and it wouldnt start. you might have a crack in the cap, was it raining outside when this happened? if so, thats prolly it, or you have a bad connection with ur coil wire. hope this helps ya bud.
EDIT: sorry, i didnt know u were talking about the volvo, so rephrase the "ur truck" part