weird problem with new truck

[72xmulch]

Hey! I am acquiring a 94 stx manual 4x4 and i am trying to figure out what is wrong with it. I am not totally sure it is the 4.0, it may be the 3.0. anyway,
while driving downhill only, the engine will start to fart out like it is running out of gas or something is starving it. it does not happen when it drives up or straight, only down. what would cause something like this? Other than that, everything seems in good strong working order...

 

[97ranger4x4]

Well since it is a new truck what do you know about the maintence?

A few general things to check.

Air Filter
Spark Plugs
Wires
Fuel Filter (replace anyways)
PCV valve
Fuel Pressure regulator


Another thing you can do if you have a fuel pressure tester (you may be able to rent one from autozone) is to find a steep hill park your truck facing downhill, and see if your getting enough fuel pressure. Compare to flat and uphill. Test at idle and 2k rpms.

 

[72xmulch]

lets say it's the fuel pump, why would it only cut-off going downhill?

thanks for helping...
ernie

 

[97ranger4x4]

Yeh I wanted to see if you still have fuel pressure going downhill. how steep of a grade are you talking about? Like just your normal hill or like 4 wheeling with your tires grabbing on for dear life?

 

[72xmulch]

just your normal hill

 

[97ranger4x4]

yeh that is really weird. I have no idea what could cause it to starve itself. Could it be getting flooded?

 

[LEVE]

I'm wondering if the fuel tank baffle has come loose? The fuel pump should sit in a "well" full of fuel if going up hill or down hill. If one of the baffles has broken loose, the fuel sloshes forward out of the reach of the siphon. To be fair, I've only seen this once on 20 year old Jeep XJ about 3 years ago.