I went thru this recently...The IPR [Internal Pressure Regulator] needs 500 PSI on start up in order to allow the start sequence. I was told it could simply be that you are using 5W20 oil and when the truck is warm/hot it doesn't have the viscosity to get past the IPR 500psi minimum, or maybe the oil qty is low. I see that most guys are running 15W40 on these types of boards which would help eliminate the above mentioned problem...However, if you have luck like I do...here is what my deal was: There is a fitting on the IPR that was improved from 06/06+up PSD's. My truck is a 05/06 production and had the old fitting on the IPR, which leaked like a bugger when hot which left me waiting for a tow truck recently. Be certain you tell your Ford Dealer about this upgraded IPR fitting when you drop it off or you'll be waiting a freaking week for your ride like I did
HTH
Jim
