What recommened grade of gas to fill up your expedition?

[FordGirl1983]

What recommended grade of gas to fill up your expedition?

I haven't been in this forum in a while but just want to ask what's the recommended gas grade to fill up your expedition with? I know regular gas makes that "pinging" noise and I heard regular is not really good for your expo. Thanks for your kind reply.

 

[IMINYOURCHAIR]

I just use the 87 grade and have no problems on my '97 expy

 

[FordGirl1983]

Thank you. Well I stopped using regular and started using midgrade, made a big difference of the performance, no funny noises. I don't know if I wanna go back to regular. Glad the gas prices are dropping.

 

[stamp11127]

Unless you have a 5.4 DOHC your engine is designed for 87 octane. If it is pinging on that octane you have a problem that is causing pre - ignition.

 

[FordGirl1983]

Oops sorry I forgot to mentioned what engine I have. It's an '99 eddie bauer 5.4. triton V8.

 

[IMINYOURCHAIR]

let's hope it's not the knock sensor. that sucker is buried under the intake on mine.

 

[FordGirl1983]

Knock sensor? Where's that located may I ask?

 

[FordGirl1983]

I'll try my best to describe the noise I heard. My expo is currently at 302k miles and still counting.

 

[stamp11127]

Have you changed the timing chains?

 

[FordGirl1983]

No, the timing chains has not been changed since we owned it. Had it since 2012.

 

[FordGirl1983]

When accelerating on the road, the noise get a bit louder. Oh I don't think it was a "pinging" noise, it's more like a bubbling, flapping noise. I try my best to describe the noise better lol.

 

[98EXPnSRQ]

I had a slight ping when accelerating on 87 octane. It went away when I changed the spark plugs.

 

[FordGirl1983]

A little update this morning on my commute, I filled it with mid grade and the rattling sound went away. I assumed that sound is from "bad gas". That's all I know so far.

 

[98EXPnSRQ]

Yep, bad gas will do it too. Switch gas stations.

 

[FordGirl1983]

Yes sure did switched gas stations.

 

[montecarlo31]

What are you seeing for timing advance and what are you seeing for retard? If it's going away with a 2 point increase sounds like timing or a plug issue. I'd test coils and replace plugs / wires. While you are in there might as well do air and fuel filters to knock out the big stuff.

 

[toms89]

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.

 

[tojohnso]

in my '99 the only issue I had was when I put in 93 thinking I would get better mileage on the highway. If the engine isn't tuned for it, bad idea. I normally filled with 87/89 whichever was available and cheaper. I do the same now with my '11.

 

[hammerg26]

Unless you have a 5.4 DOHC your engine is designed for 87 octane. If it is pinging on that octane you have a problem that is causing pre - ignition.

What octane is the 99 5.4 designed for?

 

[thewishkah]

I used to use 87 now I mostly use 89, with 87 the truck felt sluggish and would rough idle once in a while. Even after replacing the air filter, gas filter, spark plugs, pcv valve and cleaning the egr ports that were mostly clogged. All of those things didn't help my gas mileage at all. Never had a CEL but I think my coil packs are next on the list. I decided to try 89 after gas prices started to fall and it runs better, and has more pep when on the pedal.