I have a 1995 Dodge Ram 1500 V8 Manual. I have not had problems with it in the past and have only now experienced this. I was making a trip from Fargo, ND to Dickinson, ND which is about 290 miles. I filled up on gas in Fargo and drove about an hour and a half before experiencing the first problem. I was traveling at 70mph in 5th gear, but as I was going my truck suddenly lost power but it never completely died. I lost speed from 70mph to 40mph. My clutch stayed in gear and I did not experience a revving of the engine. So I am not thinking clutch. There were two pops outside the truck and I believe they were backfire from the engine. I pulled over to the side and checked over the truck, but noticed nothing wrong. So I started driving again and got about 30 miles before the same thing happened again. The truck backfired twice and I lost power but never died. Again, the truck remained in gear but pushing down the accelerator in 5th gear provided no response after I initially lost speed. It did not sound like high engine RPM either. After pulling off once more and looking at the truck I was able to travel 60 miles at 70mph to the next big city. From there I traveled the next 60 miles going 55mph, and the last 30 miles I traveled at 70mph, but experienced no problems after that. I am curious if anyone has an idea of what this might be

 

The last time mine lost power the coil went out. It was playing around with me prior as I had checked it out twice before. In other words, it would quit then work, quit then work. After a few times it finally quit for good. And it was less than a year old.

Not saying it is your problem, but something to look into.

 

How many miles on the truck and have you done the plenum repair?

 

Kejobe is right, I had the same thing as Tractor107 experienced but was in an 78 ford truck, I pulled the coil plug wire (male end) and seen a blue liquid inside the female end of the coil so I took an old rag and small screw driver and soaked most of it up. I replaced the coil plug wire and the coil didn't give me an problems for like 50 miles and I had to do it again. When I got home I had an junk old ford parts truck out back that I pulled the coil off of and it once again ran good again.