What recommened grade of gas to fill up your expedition?

[1955moose]

I have a 2000 expedition 4x4 with a 5.4. Mine runs fine with 87 octane. I only have 65k miles on mine. Have someone run a scanner on your SUV to see if you have any codes present. No sense changing parts till you narrow down problem.

 

[rtbrjason]

I fill up with the highest octane possible but mine is running boost. The higher the octane the more aggressive I can get with the tune.

Have you looked into running E85? I run it full time in the Subaru and was able to pickup around 50hp and 60-70tq at the wheels just from the new fuel and some retuning.

For fun/testing purposes, I ran a 50/50 mix in the truck (Approx E40). I was able to crank up the timing a bit and definitely got a bit more power out of it.

 

[IMINYOURCHAIR]

Have you looked into running E85? I run it full time in the Subaru and was able to pickup around 50hp and 60-70tq at the wheels just from the new fuel and some retuning.

For fun/testing purposes, I ran a 50/50 mix in the truck (Approx E40). I was able to crank up the timing a bit and definitely got a bit more power out of it.

how did you get the expy to run on e40? just curious

 

[rtbrjason]

how did you get the expy to run on e40? just curious

I wasn't planning on long term use with it. I just monitored fuel trims and made sure the ECU was able to adjust. Since I'm not making big power or running boost, the stock injectors were adequate and the ECU was able to correct. I was seeing fuel trims in the positive 12-20% range.

 

[StuntMan]

I fill up 97 Octane every time. Sure the Owners manual recommends 85 but, where I am fuel is really cheap so why not.

But Meanwhile I saw this:
"To wrap things up: no, you won’t see a power or fuel efficiency increase by running high octane fuel in an engine that has been tuned and designed for Regular gas, nor will doing so perform any extra ‘cleaning’ inside the motor. On the flip side, running low octane fuel in an engine built for Premium can increase the risk of engine damage and will certainly impact that unit’s overall performance. The next time someone tries to pass these myths off on you, you can try explaining to them how octane ratings really work – or you can just smile and nod, pay for your gas and move on."

Source:Mythbusting Octane, The Truth About Gasoline

Yeah well I don't agree with that.