i have a 1992 chevy blazer 4x4. check engine light came on yesterday, after i turned off the engine, it went off.i use this vehicle to deliver the mail in. it blows black soot out of the tail pipe when i start it. has had new plugs wires almost all is new. it also smells like something is burning when my heat is on. i thought it was catalytic converter, but i took it to a auto zone and they plugged it in and it says altitude sensor, they did not know what it was. so what is a altitude sensor? is it a oxygen sensor? please help, thanks, terry anne
Optional Information:
1992 blazer 4x4 taho 4.3
Already Tried:
has almost all new parts except water pump, o2 sensor was put in last year.