Start car, runs good, drive for a mile and instant loss of power, power fluxuation, rough idle, accelerate out of it at idle, idle good then when you accelerate or try to put in drive it dies

they are correct change the fuel filters

Sure sounds like a typical case of dirty/contaminated fuel....or a broken vacumn supply hose around the intake manifold area, in neutral let it idl;e and look and listen for a hissing sound, or a broken black rubber hose.
Also have the computer scanned for any possible codes.
Another thing to look at is the catalyctic converter, put a vac. gauge on the engine and see if the vac drops to almost zero...indicating a plugged cat.

sounds like you have either a bad head gasket or a cracked head

I Have a 1999 ford f150 4.6 that back fires and is just running really ruff when idling alot of nack fire a sord of like a pulse going on what is my problem?

Usually plugged fuel filters and/or bad pumps cause loss of power at the high end (full throttle) when you are sucking down the fuel not so much at the low end.

Rough idles can be a lot of things, usually something to do with the fuel mixture or timings. Dirty injectors, distributor problems, streatched out timing chain/belts... those are a few common rough idle issues.

Has the fuel economy gone down? Does it still have good acceleration?

Peace,

Mine did this at one time, and it was only a bad plug wire. Give it a tune up and see if it works. 170k miles is awesome, I have 145k now and it runs great, but had to have ac replaced this week :( Good Luck!!

check /replace the fuel filter and check the fuel pump pressure before and after the bleed valve to the throttle injectors

idle speed sensor maybe bad. check for codes

More information needed. It could be because of a tire with a separated tread, an ignition miss, a bad spark plug, an engine problem. With so many possibilities you need to define the symptoms better. Does the engine run rough when accelerating with the transmission in park? Does it go away at higher speeds? Has it been worked on recently and deeloped a problem after that? Did it start suddenly? Is there a loss of power or difficult starting? How many miles are on the engine?

low idle speed...or the need of a tune-up