Does anyone have any ideas? We are getting what sounds like a lifter noise on TWO trucks at the shop right now. They are both identical noises. I read the TSB from Ford that says there is a noise that is normal, however I find it very hard to believe that this is normal. It is very loud. It sounds like a lifter not pumping up. One of the trucks we had the valve covers off and checked all the rocker arms, ran a compression test, and found nothing. It is very hard to convince myself and our customers that this is normal. Has there been any lifter failures? Is that a possibility? I'd love to get some feedback on this if anyone has any. Thanks in advance!