Hi guys, I am new to this Forum and I hope you can help me..

I know this topic has been brought up meny meny times, but this is crazzy andI need some Help!

I have a 1993 GMC 1500 4x4 pickup, it is Ex Cab Long Box and has a 350 and 3.73 gears. The problem is I have a 35 gallon tank ( $130 fill up ) and im only getting about 250km (155 Miles ) on 35 Gallons of gas, I drive it easy and it does not matter. Im not one to complain about something like this because its a truck, what do you expect, buy a smart car if ya dont like it, but this is crazzy!!

My Friend has the same truck, right down to the gear's and he gets twice the mileage as I do.

This is what has been replaced so far : Plugs/wires ect, 02 senser,new trans, torque converter, fuel pump,tank,all filters, intake gasket, exaust, and much much more. The motor is strong, burns no oil and I can't see it being part of the problem, Im thinking a senser of some sort, but I dont know what. Any Help would be great guys, Im never selling this truck anyways, I would just like to get some more mpg's out of it.
PS: No there are no holes in the Tank haha

Thanks

Greg Nf Canada

 

Iran into something like this back in my tech school days.A lady brought her car in saying the gas mileage was really bad, soI went over the car with a fine tooth comb. The computer was telling me it was indeed running very rich, but why? All the sensors were working properly, soI figured I'd check the fuel pressure and turns out it had about 60 psi where as it was supposed to max out at 30 psi soI figured maybe the return line was kinked of plugged but it wasn't. It turned out to be the pressure regulator.I changed it and everything went back to normal. She came back in about 2 weeks and said the gas mileage was back to where it was when the car was new, but it didn't have the power it did when it was running rich.I told her it's not a top fuel dragster it's a Buick lol. hope this helps

 

4.5 mpg is definately much lower than it should be, so you are not crazy. Good luck. Post the solution when you find it.

 

Hey Guys thanks alot, Im going to check fuel pressure for sure but i dont think she isrunning rich, Once I floored it and alot of black smoke came out. Other then that time it never smokes, Whats the best way to know if it is running rich? Is it like a Ski-doo or Dirtbike, and burn the eyes out of your head when its running rich? haha

Thanks again



Greg

 

Well .... if you got black smoke out the exhaust it is running rich.

It could be the temp. sensor for the ECU or your injector's spray pattern is out to lunch or your MAF could simply be dirty.