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2002 Yukon
313000 miles
Brand new plugs, wires last week
Tried 91 octane fuel and no change
Tried seafoam no change
Check engine light on
Check engine light will stay off if I unplug battery, and stay under 50mph(ish)- usually turns back on if I get on the freeway

Hey guys my truck listed above falls on its face when starting from a dead stop going right to full throttle. What's weird is if I push the accelerator to 3/4 or just a hair before full throttle the truck has power and accelerates harder than if I were to floor it. After a few seconds( literally), the truck will take off and rev thru the range and bang off ever gear and accelerate as one might expect from a slightly worn motor as I have.
It's dangerous at times when trying to turn into a road with traffic or other situations when I need power right off the bat. Anyone ekes have this issue? I was thinking O2 sensors next.

FFDP

iTrader: (2)

Whats the check engine lights code number??