I have a 1994 GMC 1500 4.3L and I'm loosing power when I get up around 65-70 mph on the highway. I think it might be my fuel filter or fuel pump since I had a new engine put in it last summer. I was just wondering if anyone knows where the fuel filter is located on this model of truck. Thanks.

 

its under the truck,on the left framerail..pretty much under the driver

 

Ok, thanks. I figured that I would see if that needed replaced before I messed around with the fuel pump.

 

more then likely its either your 4.3 itself or your rear end gearing.

 

I thought it might be the engine but I bought a completely new one by Jasper Engines and they supposedly fixed the problems that the 4.3 had. The engine idles good at rest and accelerates good from a stop so I kinda thought at higher speeds it might be a fuel delivery problem. but im no expert just a college student trying to fix things on my own to save money. Thanks for your help.

 

did the truck originally have a 4.3 in it?

 

Yeah it had a 4.3 in it. It idles and perfoms ok at low speeds it just has trouble when I get up at higher speeds over 60. My mpg has dropped a lot over the last week or so also. I was driving around town today and I used a 1/4 take of gas, but i only drove 30 miles. I figure its either getting too much fuel or not enough. Im not sure though.