My mom has a 2002 Tahoe With the 4.8 and it has been a tank. We didn't touch anything other than brakes and oil. Bought it with less than 40k and has 130,000 on it. The 4.8 is a splendid motor and when you replace the bolts that hold the heads and the pistons to the crank, slap two turbos on it, put 110 race gas in it and turn up the boost, it'll do 1,200 hp reliably. Hot rod proved it