Ignition Problems with '87 5.0. HELP!!!

[Mr 5 0]

Your '87 Mustang should have a TFI module, located next to the distributor, as in this photo:

http://www.coolcats.net/tech/ts/tfi1.jpg

The TFI module tends to quit at hot temperatures, not cold so I doubt that's the culprit here. Your recent tune-up absolves those parts from being the problem so before you get into expensive ignition replacements, do the simple stuff, first.

You may just need a new battery; have it checked at an auto parts store or your friendly local garage to see what it's condition is and consider installing new battery cables, too. Your starter should also be checked for efficency, especially if it's been in there a long time. A simple voltmeter test will give you a quick idea of the battery condition. Go from there.