Ford Repair Questions? Ask a Mechanic for Answers ASAP
It sounds like you may have an issue with the timing belt. If it's slipped or the truck has jumped time it's going to have a complete loss of power and you may have the lawnmower sound. This is because it's not firing when it should be. 90 psi is not good compression to be honest.
HERE is a link for checking the cam sprocket through the plug in the timing cover.
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