Fuel? Spark? or both?

I have been running my tank pretty low these days due to the gas prices abd my truck started acting up alittle at idle but does fine driving down the road. Well today sh*t hit the fan and now I cant maintain an idle at a light! It just wants to die but when Im cruising down the road it does just fine but as soon as I stop at a light I have to keep my foot on the gas to keep her going. I was messing around with it today and was watching my tac and it started jumping erratically without any reason (increased or decreased engine speed) last time this happend I checked my plug wires and found one had melted. Ok easy fix replaced the wires. I have since then hooked my tach up to my coil terminal the right way instead of running it off the plug wire so could my coil be going out??? Would a coil run fine at certain rpms and cut out at low ones?? Or is it my fuel system? should I replace my fuel pump and purge my lines? Drop the tank inspect and clean? Its my baby and my daily so I have to drive her and fix her on my days off just wondering if anybody else has experienced this and could point me in the right direction without me haveing to drop the cash and cover all the options. Any help much appreciated, thanx in advance.

I had similar symptoms a few months ago after I had the engine washed. One of the wires to the engine controls had shorted with the water and blew a fuse. Mine's an '86 with a carb. It would drive fine, but wouldn't idle without my foot on the gas. Before you go any further check your "engine" fuse.

hope this helps.

Thank you. That was the first thing I checked should have mentioned that. Yeah I've blown that one befor trying to put in a stereo. I guess I should mention that I just recently ran a amp and sub but it has no effect with or without it. I even disconnected the amp power wire and the remote wire from the stereo and took the face off and still the same thing. All fuses appear to be good. It was acting up befor the sub though.

sorry i don't have a fix for you but it seems like that's a common problem. mine did it for a while and then stopped, and i remember reading a couple other ppl's similar discriptions. maybe you can search the forums i know you'll find something.

you might have picked up some crap from running your tank low try a new fuel filter