'88 5.0 horrible rev problem

I started getting a idle and rev problem awhile back. It would start fine, then it would rev up to sometimes 2700rpm and sometimes 4000rpm, and then it idles down and sometimes dies. Sometimes it won't idle down by itself. I would kick the throttle and it would go down, but then it would rev up right away again, and then back down, then up, then down, and so on... After it started happening, i smelt fuel! The pressure fuel line off of the gas tank was resting on my tailpipe, and melted a hole in it, so it was loosing fuel pressure. So I put new lines on from pump (tank) to filter and hard line. That solved the problem for approximately 4 hours! Now it's doing the same thing all over again!! Except this time, the lines seem fine. No kinks or holes, and are routed nicer than before (away from tailpipe). Any ideas?

what size fuel pressure regulater are you using?

Tps

what size fuel pressure regulater are you using?

Stock regulator? Not sure what mod's the car has or if has any, but before these problems, the car ran very strong. It does have x-pipe following with dual flowmaster back. No catilitic converters, but has both O2 sensors still. I had it for a year before the car started doing this. ???????? Could the fuel line have a slight blockage somewhere?

Tps

Thats a possibility. If not??????

TpsOr Idle Air Contro valve.