seafoam in the gas tank and oil.......deep creep in throttle body, intake manifold and cylinder head.
I use it everytime I change plugs on a car.
1. just pull out the plugs.
2. spray the deep creep.
3. let it sit for about 10 mins with the old plugs in.
4. start the car.
5. run till the smoke is all gone (trust me, you will have alot of smoke).
6. then change your plugs.