'93 Chevy Cheyenne 4 WD uses excessive fuel (4.3 V6)

Oxygen sensors are identified by bank and sensor position. Sensor 1 is always pre catalytic converter, sensor two is always post catalytic converter. If an engine is a 4 or 6 cylinder engine the whole engine is considered bank 1, if an engine is a V6, V8, V10....., the engine bank containing cylinder number 1 (first cylinder in the firing order) is considered Bank 1, the other bank is considered Bank 2. Interpretation Oxygen sensor designation B2S1 refers to Bank 2 Sensor 1, it will be the sensor on the engine side of the catalytic converter in bank two. Check this link to determine the cylinder that contains cylinder number 1. http://www.wellsve.com/custom_searches/ds_firing.php Wells Search Parts Catalog

Have the fuel pressure under load monitored and have the MAF sensor return signal checked. Also make sure you don't have excessive backpressure in the exhaust system.

Ghost, Check the attached links vacuum line diagrams for 1993 4.3 vortec, Good luck
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Repair Guides Vacuum Diagrams Vacuum Diagrams AutoZone com
4 3 vortec vacuum diagram Google Search

I suggest putting a pressure gauge on the fuel line bleeder valve and check the pressure coming from the pump. If the pump is getting weak it will cause the truck to surge. Could also be the catalytic converter stopping up as well. I'd check fuel pressure first. Hope this helps you out.

Vacuum leaks, or leaks after the MAF sensor. Exhaust leaks, intake leaks. Wiring for MAF and O2

no it will not work as these are 2 different style bodies.the 83 has the tanks on the outside of the frame and no fuel pump in tank.the 93 tank is located inside the frame rails and has a electric pump in the tank.

When the key switch is off and the engine is not running, do you have power to the coil ? Could be a problem with the key switch.

look at the fuel lines and injectors for signs of leakage.

have you tried checking your fuel filter?

Have someone do a back pressure test on you catalytic converter. I had the same problem and it turned out that my converter was almost completely plugged. I was also getting a check engine light indicating a misfire on cylinder 4. Once the converter was replaced, the problems went away.