Dropping mileage

[tlxreed]

Hi all,

My trusty '78 transporters is starting to get less miles per gallon. I'm noticing my average of 18 mpg has now dropped to around 13 mpg for several fill ups. Also starting recently, when the engine is cold, I'm feeling a lugging sensation like the motor is not quite hitting on all cylinders.

I've just had the carburetor replaced with an electronic version. This problem seems to precede the replacement. Should I be checking the spark plugs or is it possible a fuel injector has gotten plugged up?

Thanks for any tips on how to get this fixed.

[TexasAirCooler]

Hello tlx,

I'm not a master on the later type 3 & 4 motors, I do fine on on the type 1 motors. If I can't help you I'll get you in touch with someone that can.
This could be one or more problems. Simple ones first.

Do you use a Ethanol removal/ displacement chemical?
When was the fuel filter change last?
How old are the spark plugs?

[tlxreed]

I don't use any displacement chemicals. As for the other two, you know, I don't know. Guess I should get out there this weekend and replace both and see how it goes from there.

[TexasAirCooler]

It would help to use a Ethanol removal/ displacement like StarTron Gas Additive or Sta-Bil Ethanol Treatment unless your using a Ethanol free fuel already.