Does anyone have any Idea what this could be? First it started running rough and I found a couple bad Spark plug wires ok fixed ran great. Then on the interstate one night it started cutting out and backfiring losing all power and then when I finally got you town it just died and would not start till the next morning. then just got progressively worst. I thought it was the Fuel pump so I put a new pump and Filter on it and Bam it was running great. then I took it up on the interstate to see how she would run at high speeds and it started cutting out again and missing severely. Now when it's in Idle it surges up to 2000 rpm's and then it will drop down to normal then surge again and fluctuate there for a few min then drop back down and die. Act's like it's vapor locking it was actually getting somewhat warm over the 200 mark at least when I shut it off. I have no clue what's wrong with it.... I'm at a loss here and I'm not sure what to do....Any in site is helpful please.