My dad has a 93 W250 with auto. His mileage just plain SUCKS. Summer blend gives around 11 MPG's, so you can imagine how pathetic winter blend is. He's added a K&N air filter and a 4" exhaust. The inter cooler has also been replaced, but it's still horrible. My question is can and do the injector pumps and lift pumps go south? Wear out? Any ideas where to look? Injectors maybe? Thanks in advance.
Normally the mechanical lift pumps are pretty reliable, I have not seen many failures with them but I have seen some. Injector pumps are not too bad if you have been running clean fuel, getting over 250-300K out of them is pretty normal. Since the introduction of low sulfur fuel we have seen a big increase in pump failures, run a good lubricating fuel additive like Stanadyne Performance Formula. We got great deals on injectors this month if you are interested PM for some pricing. hope this helps...
How many miles on the truck? Any guages? Several possibilities, boost leak, stuck injector, worn injection pump. Assumin all the filters have been replaced.
I have the same truck but stick and get 20mpg empty. And 15-10 pulling trailers. that milage is before and after. I have a bank kit on it.I got 300k+ and just rebuilt the injection pump and injectors. and had it retimed. I did replace the lift pump at 100k.
