Review on Dorman 917-257 Engine Variable Valve Timing (VVT) Sprocket for Chevrolet/Pontiac/Toyota Models: Ultimate Compatibility and Efficiency by John Collins

This fixed the starting rumble on my 04 Corolla, with the right tools anyone can do the job. I have personally used an air gun (to remove the original cam), 17 I believe 10 and 12, and a torque wrench. REALLY IMPORTANT NOTE, the cam is in the unlocked state, so DO NOT TURN IT until it is tightened to 40 ft-lbs. You can check if it's still in the unlocked position by twisting it sideways just a millimeter, but no more or else you'll lock it like I did. You will know if it is blocked. Torque specs are 10 ft lbs for small cam covers and 17 lbs for a large cam cover. I took mine off, marked the timing, unscrewed all the camshaft cover bolts a half turn, then loosened them. slowly (keep it in a safe place. Then put the elastic cord on the chain so you don't waste time down. Pull both cams up to get more play and wiggle the outlet cam first and then with the intake cam Change your part and LOTS of oil on reassembly.