1997 Dodge Caravan maybe electrical

im the 3rd owner of my 1997 dodge caravan, my cousin owned it before me, and the orignal ower before him. it has 85000 orignal miles on it. on easter weekend 2010 i drove to delaware from nj, everything was fine until, on the turnpike i hear this loud bangging noise, i thought i had a flat, but there wasnt anything wrong with the tires or under the van, i did not hit the little rumble strip. i pull away and i still hear it, i get pass 50mph and it stopped. then we finally get to delaware and we are on city streets now, i turn onto one street and there isnt any incline to the road at all, i accelerate and the rpm's go up to 5 but the speedometer stayed at 30mph, and the check engine light came on, i thought right away the tranny is going. it didnt do it again. but i asked the local auto parts store what that could have been, he scanned tha van to see if it was a sensor for the tranny, but it wasnt, 2 manufactoers codes come up, 1496 5 VOLT OUTPUT TO LOW, 1695 NO BODY CCD MESSAGE, and he told us to clean the battery termenals, so we did, come to find out there is an after market alarm on it, and a lolack. so after cleaning battery, the van wouldnt start, the alarm was going off though, so we snipped the wire, alarm went off but car still wouldnt start, we put wire back together then called lojack and he gave me a bypass to start the van, it started, but i shut it off then tried to turn it back on and it wouldnt start. so evently we towed it back to jersey and took it to pepboys, they said if it has to do with an alarm then they couldnt help me, so i called an alarm place and i described everything to them and the noise the ignigtion was making and he said it was the starter, so pepboys replaced the starter, the van worked then 15 mins later the check engine light came back on, we scanned the van and the same codes came back, now the car putters really bad when i start it up, like its about to shut off, so i let it sit for a minaute and then for the rest of useage its fine, unless i let it sit for a long time then it does the puttering thing again, i called a crysller dealer person and they said it coupld be a wiring/electrical problem. i love my van and it has low milage for a 1997 and i would like to keep it, but i heard the electrical is a bad sign please help thank you in advance renee nj