Octane Choice

[Silver Ex]

Ford recommends 87 octane in the owner's manual for my 5.4L '98 Ex XLT. What problems/concerns would there be with bumping up to 89 or even 92 octane? I know the owner's manual is explicit about using ONLY 87 octane in my wife's '01 Mustang w/3.8L V6. The owner's manual states that it will cause poor performance and most likely will cause it to throw a check engine light.

Thoughts?

 

[RUFFSTUFF]

Empties your wallet way too fast...

 

[Grasshopper]

Use the lowest octane that doesn't make it knock.
The PCM controls the spark, A/F and all that jazz and if it's tuned for 87, then that's what the manual will say and that's what you need to use. No reason whatsoever to use anything higher.
My Thunderbird (supercharged and tuned) needs at least 92 octane or it'll detonate to heck! Different application.

 

[JUST4FUN]

useing higher octaine will cause deposits on the piston tops
then when you stop useing 92 octaine and go back to 87
will cause ping due to the deposits left by the 93 octaine

 

[mustangrfast88]

just stick with the 87 oct and you will be ok i mean there are ways to make more power with the higer oct but you got ot reprogram your computer and even using 87 oct and reprogaming your computer you will make more power then with 93 oct and not reprograming and 87 oct is cheaper too