Okay, went out to double check to make sure that we were getting fire to #5 cylinder and the battery (which the dealer told us over 3 yrs ago was bad) was dead. Not totally, radio and internal lights worked but not enough juice to turn over engine. So, we charged the battery and "fiddled with # 5 plug wire. Next day truck cranked, ran fine, check engine light was out. We bought new battery so either it was a loose plug wire on # 5 or the
battery. Don't know if the battery could have caused the problem or not. Thought that I would put it here in case it might help someone else looking for answers in the future. Sure would beat tearing the injectors apart or replacing ignition parts, which is where we were headed.
Rev, thank you for your help along the way!