1996 Dodge Ram 2500 chugs and dies

I bought this truck about 8 months ago, and replaced the EVAC system right off. Now, it’s doing this thing where, when driving uphill, it chugs and makes a loud metal clunking sound. Also, as I slow, it tries to accelerate on its own (with my foot on the brake), and if I sit for too long at a stop (idling), it dies. Starts right up again, but it sucks having to start my truck on the freeway in slow/stopped conditions. Is it my fuel pump or my transmission? Help!

Is it a diesel? If so, I would first check the lift pump pressure (should be around 8-10 psi, I believe). They are notorious for failing on these, and when they do, the expen$ive injector pump soon goes too. I had this problem recently, and the lift pump was the culprit. You can get a lift pump many places on line, and they go anywhere from about $125 - $250. Installation is a bit of a pain, since you have to drop the fuel tank. I just let my mechanic do all the nasty work.