do me a favor, crank it, leave in park, press brake and give it some accelerator at the same time WITHOUT spinning tires. if you hear the ticking/rattling noise its more than likely exhaust manifold leak. Have someone else walk around front end while doing this with their ears listening at the front fender wells.
put it back in park, then rev it up. if you dont hear the same ticking, i can almost say it IS exhaust manifold/
2004 F150 Supercab Lariat 4x4
5.4 3V Triton V8 | Oxford White | UltraGauge | Ford OEM 20'' Wheels | Nitto Terra Grapplers 265/75/20 | AutoSpring 2.5'' Leveling Kit | XCal2 with VMP Tunes (87 Perf & 87 Tow) | Hella 500FFs Custom Mounted Behind Grill | 09+ Mirrors w/ Chrome Skull Cap (Pwr/Heat/Sig) | 2010 F-150 Efans w/ DC Controls Controller