I can't speak to valve train problems as I never have had any with my Toys. I have a 91 pre-Taco, that has cost me tires brakes and a clutch in 25 yrs. I have had an 01 RAV (wife), 01 Solara, 05 RAV (wife with no intention of trading it), 05 Solara (wish they were still made), and a 13 4Runner...