1994 Jeep Cherokee MY Jeep KEEPS SHUTTING OFF WHILE I'M DRI

Okay here it goes. I bought a Jeep Cherokee 1994 Limited. The engine was about to go on it, but I had a Jeep Grand Cherokee 1996 and I had just bought a new engine for it. Unfortunately I wrecked the Jeep Grand Cherokee 1996 in the snow. My dad took both jeeps to a friend of his to take the out the 94's engine and replace it with the new one from the 96. Everything was perfectly fine for about 3 months. Then my check engine light came on, but we couldn't figure out why. After that my back right side window stopped working along with my back windshield wipers. All of the sudden my jeep starts jerking, like it was missing or something. My dad insisted on taking my jeep back to his friend and his friend said it was a fuel leak and that a safety switch was broken. He replaced them and 2 days later the jeep started jerking really fast forward and then it would skip a little and then it cut off. We checked the spark plugs and they were fine, actually they are brand new. I started to notice that the jeep would mainly cut off if it had rained or if it was moist outside. Then I figure ah ha it's the distributer cap and router button. I replace them b/c I was right they were covered in what looked like oil and metal shavings. I drove it about 15 miles to work and it was fine. When I started to drive it home it started jerking again and shut off. Usually when it cuts off I have to wait a while for it to start again, but it was 1:30am and I'm was pretty impatient and wanted to get home. I popped the hood and pressed on the spark plugs then started the jeep. It barely got me home. When it cuts off the brakes get stiff, the power of steering cuts off, the headlights flicker, and the battery stays on. Another thing I noticed is that the r/min looks like it's stuck and when it moves it acts funny when I hit the 2. Any information or advice you could give me would be wonderful and greatly appreciated.