Engine wont start when hot!!! help!

[meknized]

Hey, I think I MIGHT know what the problem is. My dad has an '87 Cougar XR-7 that has had the '89 5.0 HO swap, ported heads, cobra intake, exhaust etc etc etc. He had the exact same problem, after it became hot it wouldn't start and would barely crank. Like you after it was cold it would fire right up. I spent probably two hours trying to figure it out and like you it had spark, fuel, everything. One thing I did notice was that the spark was actually a yellow not a blue even though it has full MSD ignition. Well, to make the story short(er) The ground strap from the firewall to the back of the head was totally loose, plus my dad had grounded the negative battery cable to the inner fender instead of the block. I tightened the firewall ground and moved the battery cable to the block and BOOM it fired right up and hasn't had that problem since. It even seemed to have more power. Check the grounds, look for corrosion, tighten everything down and make sure all ground straps are there. Let me know if that was it. Good luck!