My 89 Gt (stock 5.0 with mild AOD and 3.73's) is having some serious issues. It runs strong and without any hesitation/stumbling. After it gets warmed up, and driven a bit (30-40 miles), it starts dying! It won't idle at all, and if you can get it to stay running, it has NO power, and its backfiring/popping in the exhaust... Its left me stranded about 3 times in the past few days... what could be causing this? I've done a complete tune-up within the last 100 miles... plugs, wires, distrib cap, rotor..... The few things I've thought it could be are: The Throttle position sensor, fuel pump, fuel filter, clogged cats, egr valve?? Am I missing anything...... Will a computer pull a code even when its not acting up?? This is my daily driver, and I need it fixed fast!