better MPG with MAP un-plugged

[stroker101]

why does the truck get better fuel mileage when the MAP sensor is un-plugged? the sensor is brand new but the mileage is really going south.
is there something else to replace? need your help, thanks!

[STurbo90]

my guess would be that because when the map is unplugged the pcm does not know how much to fuel the engine. It is using a default value.

So when you are getting on it the pcm doesn't know to add more fuel to the mix to compensate for the higher volume of air being introduced.

[stroker101]

the truck runs really strong. lacks no power any where. smokes very lightly upon cold start up. the oil is fresh, the FPR screen is clean, new fuel filter, no fuel leaks. lift pump is fairly new. what else should i look at? could it be an injector issue? ICP sensor? incorrect MAP sensor(again)? any reply will be appreciated. thanks

[stroker101]

more digging around revealed the tubing from the pass. side exh. manifold to the EBPS had fairly large hole in it and several other spots that were to the point of blowing out.
went to Ford to order, but not fully recovered from Hurricane Gustav. so i just cut the ends off and installed 5/16 Ref. tubing in it's place. sensor had zero build up.
hopefully this will help bring up the mileage

[stroker101]

well fella's, this had little to zero impact on increasing the milage. i can see the fuel gauge move. no fuel leaks, oil is fine in appearance, smell and appearance(fresh)
truck runs really strong. no black or blue smoke out of the pipe. well some blk smoke when i put my foot into it.

HELP NEEDED...PLEASE

[91diesel]

check all the wires going from the map to the pcm.