I don't know how to explain it, but for some reason, when I have a half a tank or close to it, the truck seems to start funny. It starts on the first try instantly, but it doesn't "shake as much as if the tank was full. It just seems to start a little slower and the RPMs come up a little slower after letting go of the key. Does this indicate a problem? The truck only has almost 88k and the fuel filter is brand new. The last time I changed it before that was only 12k before that.

EDIT: I just filled the tank and now it starts instantly and shakes the whole car when I turn the key and let go. It seems a bit "weaker" when the tank is around 1/2 a tank. I never let it go below 1/2 a tank unless it is an emergency, then I don't let it go below 1/3 or 1/4.

 

Is that like,,, Half a tank full or Half a tank Empty
Just Joking,,,Thats Strange, Hummmmmm

 

Could there be contamination in the bottom of the tank of some kind? Water? I have used Lucas in the tank every 2-4 fillups. I just put it in tonight when I filled the tank. It wasn't in the tank in the previous fillup or the one before.

 

Are you saying it is a LUCAS Addict ? It only run good with the additive in the Gasoline ? How long has it been doing this ?

 

Months, but that was before I was seriously using the Lucas in the tank to get better gas mileage. I think the fuel gauge is also going bad. It would show 3/4 of a tank after it burned 1/2 a tank, but then it becomes accurate again after 1/2 a tank. Maybe I should stop using LUCAS and try Techron or something.

 

Could there be some kind of contamination in the tank that only affects it at 1/2 a tank? Maybe I should drive it until the tank gets to 1/4 a tank and siphon the remaining gas and see if the gas is contaminated?

 

sounding like a weak fuel pump. those additives are horse **** IMO, even lucas (although there engine lubricants are good), if gas millage was that easy to increase everyone would be using additives

get your pump tested.

 

I agree, never been a Additive fan . Is the Fuel pump making a lot of Noise when you first turn the key on and while the Engine is running ?

 

Check the fuel pump. The fuel pump is a 2 stage operation, first stage fills a "cup", 2nd stage draws from the cup and delivers the pressurized fuel. Might be stage one is going bad on you and you only have a steady supply of fuel when the tank level is above the lip of the cup.

 

When I turn the key on, the fuel pump makes it's usual sound for a couple seconds. When the engine is running, I can hear it clearly standing next to the car, like I have been able to do for a long time. Maybe it really isn't anything and it is my imagination since I do alot of short trips between startups and the battery cables are probably corroded and that is what is making it hard to start?