My neighbor has a 93 xtra cab dually 2wd with a auto that is almost completely stock with just under 100k miles. He was driving it the other day and it suddenly lost power in the upper rpm, speeds over 40mph. At the same time it's doing this it's blowing white smoke. He says that it runs fine at lower rpm and slower speeds, but it has no power on the top end. I was thinking it was either a timing issue, or air in the fuel? What do you guys think?

 

air in the fuel system, maybe a bad lift pump?

 

It could be a super clogged filter or some junk in the pickup assy. in the tank.

I wouldn't suggest running it too hard while it's doing that because white smoke means that it is running lean and there is a bigger chance of burning up valve seats/seals in that condition. Just a thought but it may have something to do with the ksb, any connection issues there?

 

i dont think its cold enough for the ksb to matter

 

Sounds similar to what just happened to mine in a thread I started a couple days ago.
Still trying to figure it out

 

KISS fuel filter first

 

Second. All in favor?

 

sounds good to me
mine did that, i changed the fuel and problem solved
we have a lot of problems with the five tons in the army out here at ft irwin with jp8 and the blowing sand messes up the fuel filters

 

He said the fuel filter had been changed recently. I'm leaning towards air in the too, whats the best way to check for that? He doesn't drive the truck much and he's pretty good to it when he does.

 

if he just changed the fuel filter, check the fuel heater gasket thats usally the cuprit

 

I talked to the neighbor today, he thinks he has water in the fuel since he rarely drives the truck. He is gonna change the fuel filter again this weekend.