1986 iroc/305 tpi (f)/19lb inj/50-psi fuel press/sr torq heads/mild eb cam/.030 over/9.4-1 comp/paxton 6-psi. problem has been intermittent both before and after engine mods.
its allways code 33 (maf high) very slight stumble at idle just before engine light comes on, other than that it runs smooth, but seems to not have enough spark advance when accellerating on highway.
my bible is Ben Watsons-how to repair chev tpi. this book says code 33 is very hard to diagnose and you may need to take an expensive guess, so i did. one by one i replaced: maf sensor (new bosch) all-3 relays (power/burnoff/fuel pump) and their connectors w/pigtail, new ecm w/updated prom. none have fixed the problem.