91 tune --> 87 fuel = bad juju - you will be a'knockin'

87 tune --> 91 fuel = loss of performance at higher rpms, but not harmful

 

cool thanks man

 

Thanks to everyone for your input on this. If there is anything else I should consider please don't hesitate to add your comments.

 

so wait, let me get this straight. will the SCT x3 i have store up to 5 stock tunes on it? like my truck is programmed right now and i have 2 perf tunes loaded on my SCT. could my friend with an f250 order a tune and i could program his truck too while mine is also programmed?

 

LOL!

No - 3 tunes for YOUR truck, plus YOUR stock tune

The tuner is VIN-locked to one truck at a time.

You can flash/reflash YOUR truck to your heart's content....

 

hahah oooookay i see now, i was gunna say wow i could make some money off this if it really works that way... haha

 

just testing signature to see if it works.

 

You have to click on the option under the post box each time.

 

looks like I got it. thx