Nissan Repair: intermittent rough idling/missing, rush hour traffic, nissan quest

Question
I have a 1999 Nissan Quest with about 90,000 miles on it. In the last 3 months, I had the egr valve replaced, the three hardest to get to fuel injectors replaced, and I had a major tune up (new plugs, etc) all done at a dealership. Since then, I have had an intermittent rough idling or "missing" only when I am idling like in rush hour traffic or at a stop light. It is so bad that I am afraid the van will just die and leave me stranded but so far that hasn't happened. The last three times, it has been pouring down rain. Could something be getting wet? I am at a loss because the rest of the time it runs great. When I take it in, the mechanics look at me like I am crazy but it never did this before they "fixed it". Can you help me?Thanks.

Answer
Sharon,

THese are the worst to get corrected.  If the van will not act up when the shop has it it is difficult for them to understand the problem.  If it is only doing it when it is raining I would say it has something to do with electrical.  I would have them check the plug wires and coils to make sure there is nothing cracked or loose.