MustangForums.com - WHAT!!!! No vacuum leak?

for the past month or so i've been trying to find the reason my car runs about 80% of the power it should be running. It doesn't do this all the time, just spurts of a few seconds it just lags then picks up and hauls ass. Ever since i bought the car which has been about 2 months, when i would crank it the first of the day, or second depending on how long its sat, usually over a period of about 4 hours, it would idle poorly, and would damn near choke and die if gave it gas until it warmed up for about 5 minutes. So i threw on a new fuel filter (didn't work) added fuel treatment (didn't work) checked for vacuum leaks (none found). So...... i finally found a guy on here that was having the EXACT same problem as me, he said he found a vacuum leak so he bought new hoses. So i took my car to ford today because i looked and looked never found any leaks. i don't know if im relieved of ticked off that they didn't find a leak either. good news is they didn't charge me for finding nothing which shocked me. So now its time to start small, i've already bought 2 new coil packs, i figure my problem is either an ignition problem or a fuel system problem. New plugs, wires, coil packs, and fuel pump is on my list to install, i also have a new thermostat (198 degree) because i heard a low degree thermostat can make your car run rich, which mine does, not to mention my car runs extremely cool, my gauge is barely over the lowest mark even after driving for an hour. anyone know of anything else i should look into, i also though about checking out the MAF, couldn't hurt