i have an 02 3500 5 speed with 90,000 on it. just yesterday it started surging going down the interstate at about 2k rpm. it felt electrical cause it was all or nothing and there was no smoke. i pulled off the interstate and cut the truck off. went to start it and it took about 4 to 5 cranks to start it. could it be the throttle position sensor? i wouldnt think the TPS would cause hard starts. i have had some people tell me injectors due to some times if i go to WOT it backfires while blowing white smoke. it has about 15 to 20 psi of fuel pressure to the vp at idle. REALLY hope its not he vp. any ideas on this? thanks