Ok, so I went to drive to work this morning and the check engine light came on, the battery gauge dropped and then the RPM guage stopped reading, shortly afterwards All of the gauges stopped reading and my lights stopped working. Now right off hand I figured it was the alternator so I went and swapped it with a new one now the truck runs but the idle is really low, I had the guy at auto zone test the battery and the idle was around 750rpm and it idles real rough and there's a lot of unusual movement from the block. That's my problem. Oh yeah, I almost forgot, it's a '95 2x4 with a 4.0 V6. Nothing added, no mods or anything. I'm thinking one of my plugs might have a weak spark or something. I dunno, any advice?

Did you find the problem yet ?

It sounds messed up but check youre positive battery cable. I had a similar prob. and thats what it ended up being. Also check all youre grounds. Is it sending any codes?