Had a issue like that once before checked everything i could think of. Starter dragging and sounding funny. from what i was told toyota had a I.T bulliten out saying that the neg. cable to the frame was to small. clean the area and i put jumper cable to block cause i did'nt think it would help. but it did. so replace the cable with a heavier gage cable see if that helps. would have thought it would have done it all along but kinda come on all of a sudden. on the truck i did.