OK, so Rick (the Prez) congratulated me at Mustang Mania this year on making it to the event without any issues. Well, he jinxed me. When I went to leave the event, as soon as I started the car it began sputtering backfiring through the plenum, stalling, generally refusing to rev when given throttle and generally giving me mega-cr@p.

I coaxed it home and read the codes: 511 twice and 157 twice. Also, the Anti-Lock light came on a couple of times. Here's what my manual says:

157: Mass Air Flow sensor fault, low voltage. Test Condition: Continuous memory.

511: Read Only Memory (ROM) test failure. Test Condition: Key On Engine Off (KOEO).

My ECM has a Moates chip on it.

OK, how bad is it? New MAF (just replaced in the spring)? New Moates chip (just reflashed in the Spring)? Just a loose chip? New ECM? Grounding issue? All ideas welcome.