Folks,

I have a '95 XJS 4.0 LHD. 2+2 conv, Automatic, with about 57,000 miles. Good condition overall. have owned it for about 4 months.

In the last two-three weeks I've noticed that when the tank gets down to about 1/3 or 1/4, the car (sometimes) bogs out, loses power and even stalls. Then I fill the tank (93 octane) and the problem goes away. Sure feels like a fuel starvation issue. Any ideas?

bad fuel at the bottom of the tank (drain the tank)?
clogged filter?
weak fuel pump?

Any thoughts?

Ed
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95 XJS
69 XKE
70 Stingray
81 928

 

Sounds like a fuel filter and/or fuel pump... I would first try a new fuel filter.

 

Could well be the fuel level sending unit. I think you're running out of gas at 1/3-1/4 indicated.

 

Good point. Are you tracking how much fuel you're adding to the car when you're refueling?

 

Good point about the fuel sender -- but I tracked the fuel and there is plenty of gas.

 

I have a theory and time will tell if it's correct. I suspect there's water (or some sort of contaminant) in the fuel. Here's why:

1) The car stalled or bogged after a hard turn or a hard brake, which might result from mixing the contents of the tank and, thus, stirring up the water from the bottom of the tank toward the fuel intake.

2) I use 93 octane. I wonder whether that fuel is more prone to water problems because so few use it. It sits in the gas station's storage tanks. After all, I live in Louisiana and humidity here is brutal.

I put in some HEET, which is mainly isopropyl alcohol, to absorb the moisture. Let's see what happens.

 

Okay, I think my hunch was right. The bogging and stalling was due to moisture in the tank; I must have picked up some bad fuel in this humid place (Louisiana).

I put in a (RED) bottle of HEET, which apparently is 99% Isopropyl alcohol, and that improved things. Later when the fuel tank was 1/2 empty, I put in a second bottle.

Two weeks and two tanks later, the problem seems to have disappeared.