Code 33, 34, 42, and 43. Replaced the map with a known good one, no difference. If I crank the car, and shut it right back off, it sets code 33, 42 - if it runs for about 15 seconds or so (maybe 10) it sets 34 and 43. The knock sensor was disconnected, but I hooked it back up. Timing set to 10º BTDC.

I can get a ecm from the junkyard for $20, no return. How on earth can one test the ECU to see if it is bad?

not nessacerily

if you followed a diagnostic flow pattern (usually found in GM manuals) you will see that when a code sets, say a code for the MAP, its not nessacerilly the MAP that is bad..................could be bad wiring to the MAP, a clogged vacuum line, bad ecm, etc.

i suggest you follow a GM diagnostic flow chart for each of these codes

check the ignition module if the timing isnt working correctly its throw codes 33 and 34 due to an over or under rich condition. our getting EST errors 43 and 42 generally speaking that means the ignition module isnt working properly.

Ignition module was checked at Discount, all green lights. I popped the map vacuum line off, and it's got vacuum. How do you guys suggest I check the wiring for the map?

btw, I know a bad O2 is generally code 13, but would it affect any of these codes?

could the est module go bad?

I tried a new ecu, still the same codes... arg!

replace the ignition module. then take 2 aspirin and call me ithe morning.