Tansfer case switch

[manyblazers]

Merry Christmas everyone. I have a 96 Yukon and it's gas mileage has been cut in half. New pump, wires cap and rotor and plugs and gas filter and air filter and still no improvment. I was wondering if the transfer case might be stuck in 4 wheel drive. Is there a switch I can test on the case? If yes any ideas where it would be. Thanks and Happy new year to all.

 

[5280k5]

Your best bet is to jack the truck up on all fours and see if the front d/shaft is spinning
If the front axle was engaged you would feel it binding when turning and even if you were stuck in 4wd I don't know that it would cut your mileage in half. You might want to have someone look at your O2 sensors and fuel trim data with a scanner rather than throwing more parts at it.