My 2003 flex fuel 3.0 will be running fine then I can come to a complete stop and once I begin to ATTEMPT to accelerate it begins to spit sputter and back fire like it is flooded and the engine light will begin to flash but if I place the shifter in 1st gear it will drag itself up to 4500 rpms and once it reaches that it will pick back up and start running fine again I have replace the plugs wires and coil pack now my tranny is starting to go haywire this has recently become my only mode of transportation and my fiance is a cancer patient so I really need help with this problem ASAP

 

Welcome to the forum

Flashing CEL is from the misfires it means "back off the throttle or engine damage may occur"

I would Clean the MAF sensor easy and cheap

Stop by an auto parts store and have them check for engine codes, its free
WRITE THEM DOWN!!!!!!
Post them here

I would for now unplug and plug back in the TPS(throttle position sensor), 3 wire connector on upper intake by the throttle linkage
Unplugging and plugging back in cleans the contacts, do same thing for MAF sensor, you can do that on any sensor or control you see, won't hurt anything


Manual or automatic trans, the "shift to 1st" reads like automatic but..................

 

It is a automatic 2 wheel drive when it drags at take off it sounds and feels like it is towing extremely too much weight but the RPM doesn't at all match the sound. It says 2000 RPMs but it sounds like redline to the ear

 

And you matched the lay out on the coil pack wiring

3 4
2 6
1 5

Those are matched sets of spark plugs, 1/5, 2/6, 3/4 need to be opposite of each other on the coil pack, each pair fires at the same time

Very easy to reverse wires on the 5, 6, 4 side, and you would get what you got now