codes, codes and more codes

[nothinbutroad]

so im having some real trouble figuereing whats wrong with my explorer. during a koeo test i get a code 22. but during the koer test i get the codes 12, 13, 21, 32, 64, i used to get a 66 but i replaced my MAF so i no longer get that code. i have also replaced the O2 sensor. when i start her up she runs normal for a little while.... then i hear popping from what sounds like the cat/con, then dies 30sec-1min into idle( i cant even complete the koer test before it stalls) i noticed that i started having problems after i replaced my alternator, rough idle, stalls, black smoke, my volts drop, and spike, never steady, i also noticed most of the codes i get says the signal voltage is too low, i had the alternator tested, its all good. ive been messing with this truck for weeks, im out of ideas of where else i should look, replace, etc. im looking at replacing the map sensor, but idk if that would help at all, im pretty sure im trying to fix multiple problems.

 

[MrShorty]

KOEO 22 suggests a fault in the BARO sensor circuit. It would probably be worth some effort to see if the problem lies in a faulty BARO sensor.

KOER 12 and 13 are likely not very useful, because they simply indicate that the engine was running rough (which we already know because it stalls before completing the test).

KOER 21 and 64 are from the temperature sensor indicating the engine is cold. But, the engine is probably cold because it won't run long enough to warm up.

KOER 32 is interesting, because I didn't think '91's had an EGR system. Does yours have an EGR system?

Black smoke suggests that it is running rich. Have you checked the fuel pressure? Checked for gasoline coming from the vacuum port on the fuel pressure regulator?