gas milage
 

i have a 91 b2200, and my question is what causes my truck to suck as much gas as it does. It never used to go through gas as much as it does now a couple of months ago. It's a 4-cylinder. I put a new exhaust on the truck thinking that was it, but it had no effect. I only get 110-125 miles on a full tank where i used to get 300 miles for a full tank. Any suggestions on what it could be would be nice.
Thanks

RE: gas milage
 

#1..Carburetor could be at fault if float level is too high or is overflowing.
#2..The air/fuel solenoid in the carb could also be stuck causing an overly rich condition as this directly controls the fuel mixture.
#3.. The oxygen sensor could be stuck in a lean condition due to internal fault or external vacuum leak. This would also drive the mixture lean as it is the main input to control the air/fuel solenoid.
#4..Coolant thermosensor indicating a cold engine condition to the PCM which would also keep it rich and in open loop fuel control.

RE: gas milage
 

also, some times when i'm driving my truck will sometimes studder, does it more often when i gas it fast, its manual transmission, but it depends how good i start off, if i start off good in first then it dont studder, if i start off not as good it will studder, makes no sense to me..