Does it have a high idle speed? Anything else you can tell me about it?
the idle goes high just for a second or two then it goes back to normal. it has a slight miss to it.
Hmm, I'd check or replace the other tune up parts next.
I'm sorry you're not satisfied. I'm trying to help you the best I can but worn ignition parts is the most likely cause of a misfire. It's the first thing you should check. If those parts aren't worn and look ok I'd check the basics next like compression and possibly a leak down test on each cylinder. It's not the end of my answer I'm just pointing to the most possible cause for you.
It very well could be fuel pressure or a bad fuel pressure regulator. You need to do a fuel pressure check at idle then under a load and see if the pressure is good. At 80mph if that's the problem speed I'd drive it to that speed and see what the pressure it. Route the hose under the hood up where the wipers are and duct tape the gauge face to the windshield. That's what we do at the dealer. Let me know if you need more help.