Originally Posted by wlpatterson
I have a 2000 BBC 3500 4 dr.Chev.Truck thats missing the 2 sensors aft of the last muffler.I did take the VIN to chev & the drawing they provided me shows them to be there.Mine have plugs in them..I cant find any trace of a wiring harness--It gets 10 to 11 miles per gal at 55-with or without trailer??Thats what started me looking for the sensor problem..it gets the same milage with.without a trailer-Im to understand the front & rear sensors tell the computer wheather its rich or lean--Without them it retards the timing & increases the fuel?Any help provided will be greatly appreciated--
The only sensors that are used in the exhaust are oxygen sensors. Anything behind the catalytic converters would be for monitoring converter performance, they will have no effect on performance or fuel mileage. The sensors used for fuel control are as close to the manifolds as possible and would have to be in front of the converters. I would think it should have them but if it's not turning on a check engine light then it's possible that those may not have been used on that truck from the factory. If they were missing there would have to be simulators installed or the program on the computer would have to be altered to keep the check engine light off. Those trucks with the bb in them get terrible mileage, that's probably all it will get.