I have a 88 f150 5.0 EFI. It idles rough. If it drops too low 1000 rpm it just turns off. It sometimes does it at red lights or just at idle. It sometimes just to 2000 rpm out of nowhere at idle. It may have a misfire. I need help!!!

 

I realize may 2005 is a lot newer but mine was doing the same thing. I replaced the throttle body and it was fixed.

 

Check all of the PVC vacuum hoses, sometime they rot and stuck air at different times. EGR valve sensor will do this too. not sure if it sits on top of the ERG that yr. Fixed a friends 94 Towncar yesterday. Vac leak was a pcv feed hose drivers side, back of the engine by the fuel rail. The line runs from drivers side to the pass side behind and under the TB. hope this helps.