Something also to think about is percolation- I find on my 1/2 and 3/4 ton that when the engine gets warm after a drive, then I park, then after a short period- less than 1 hour or so, I need to put the pedal to the floor to start the truck- It starts right up then- It does not explain the slow cranking, but might be worth the try- But a service on the starter is not a bad idea- a clean electrical system is a happy electrical system.
BTW I have Carter W-1's on all my trucks
Sam
