My 2001 ford f150 lightning was running perfectly, i didn't use it for 2 weeks, when I tried to start it ,it fired up firs time ( like always ) but won't stay running . Any help would be great.

2 weeks is not long enough for the gas to go bad, but if it was near empty it may have gotten water from condensation in the tank. You'd be surprised how much water can collect, (depending on humidity where you live and temperature differences from day to night) even with the sealed EVAP system clean air must enter the tank as fuel is used, the EVAP prevents fumes from escaping not entering. Try some Sea-Foam, or HEET, although I am not a fan of mechanic-in-a-can stuff, those products help remove water by mixing alcohol with the water and it burns through. Be sure to read label and not get oil treatment. Now...if it was full or near full, maybe a rodent got in intake and built a nest? Happens all the time. Check air filter and intake duct before blower.

Thanks very much for your answers , as i live in the U.K. it's quite hard to find a reliable machanic that has worked on American vehicles, so i will try both of your answers. Thanks for taking the time out to answer my question. Russ.

I have the same problem with my 03'SVT Lightning. It starts up perfectly, then stalls. I have changed the fuelpumps (walbro) the iac , sparkplugs, fuelfilter and fuel relay.. but still wont run:( Any suggestions?