J.

Probably a dumb question, but did it start/run before you changed the exhaust or was it dead before you got under there. If it was dead before you crawled underneath, I'd check for spark. Does the fuel pump run (you can jump at the fuse panel)? You need spark, fuel and air to make this thing go, you know you got air. If the fuel pump (main one) runs, your most likely getting fuel. I realize this is general, but its where you need to start unless you have a reason to look elsewhere (i.e you messed with something). Also, note that the fuel injection relay can stick on cars of this age. Let us know when you no more.