sensor problem?

[meta]

I have a 1990 b2600i 4x4 and the truck will not start unless i disconnect the air temp sensor then the truck will run at about 500rpm(crappy)then i can plug it back in and it will jump up to 1100rpm. but either way when i push on the gas i still get black smoke and this condition gets worse as the truck gets warmer. I also should ad that the truck has low spark or at least i think it does, there is a yellowish/orange color and most people i talk to say it should be bright blue. Normally the truck wouldn't fire but i decided to open the spark plug gap from .44 to .70 to see if i couold get a bigger spark,well it starts but only if i disconnect the sensor. but still runs bad. any ideas?

Thanks

[Tyranitar]

Ok, this sounds like a sensor input failure to the ECM. I would inspect the circuit board of the computer and check for corrosion. Visit www.avproecm.com and click the Mazda trucks link. They have instruction and pictures of what this looks like. If yours shows signs of corrosion, you will need to have it rebuilt.

[meta]

Thanks for the info.