92 ram d150 issues, im stumped

Firstly, hello everyone. I am new to the forums and this is my first dodge. I got this truck at a good price ($400) with a clean title and just couldnt pass up the deal. Its got a 318 fuel injected mpfi. It was not running, and was told had an ignition system problem. It had a new crank sensor, and what looks like two used coils. I tried both and found that one was bad. I replaced the pickup coil and repaired some frayed or broken wires i found and it fired up, but ran terrible.
I thought it was timing, so i brought it up to tdc and comfirmed the timing mark on the HB then set the rotor to #1.
Still ran terrible. Backfiring through exhaust and seems to be missing on several, with no power. I checked the cap and rotor which both look new. Replaced the wires and cleaned the plugs which looked carbon fouled (dry, black soot).
I checked the voltages at the pickup coil, tps, map which are all within spec. The map was 4.5v not running and flucuates from 2.5-2.7 when running.
I dropped the tank to check for trash, and was good. Replaced the fuel filter.
It will start right up every time, and sometimes just feels like a misfire on multiple cylinders, and sometimes will backfire through the exhaust. If you give it any gas at all it will backfire through exhaust.

At the moment i dont have the money to throw at it until next paycheck, and im mainly fiddling with it while im off this week. But would really like some input, as it is driving me crazy.
Thanks ahead of time for any assistance, and im sorry about the long post.
John

It could be any number of things. If it's a 92 it's OBDI I believe. Can you get a scanner and check it for codes? What were the frayed / broken wires? Any clues there? Have you confirmed the plug wires are all going to the correct cylinders? Was the crank sensor clicked in good to the harness? How many miles? Wondering about timing chain...

What's the longest you've let it run - does it ever smooth out, or just run rough constantly?

Still nothing

Firstly thank you for your responses. I dont have access to a scan tool, but i did pull the codes using the ignition switch 3 times and their were no codes. I have since replaced the coil, just to check. I checked the crank sensor wiring and plug (that was a pain to get to) and all was good. The frayed wires were oil pressure sender, and some going to the trans i believe, and the orange (5v i believe) power wires where they come into one were exposed. I have checked (twice actually) the plug wire order and location which was good.

Could the timing have slipped if the timing mark is at tdc with the rotor pointing to #1?

Thanks,
John

i hate to say it but you playing with the distributor was about the worst thing you could have done. the computer on these things controls the timing and not the distributor. the distributor controls fuel sync and setting the fuel sync can be a pain in the ass on these thing especially if you don't have the right tools. also how many miles are on the engine. the heads on these engines have weak casting and are prone to cracking.