get 2 cans of seafoam. Do before oil needs to be changed. Preferably (but not mandatory) do with old plugs. Have assistant start car, unplug brake booster line (car will run rough), have assistant keep engine around 1700-2000 RPM. Slowly pour seafoam in brake booster line--car will run like shit, some white smoke will come out--this is normal. When you get about 1/3 used, quickly pour more seaform in, don't have assistant compensate throttle--the trick is toward end (total of maybe 1/2 to 2/3 bottle used) give it enough seafoam to kill the car. Let it sit for good 30 min or so. Put last 1/3 bottle in with the oil. The 2nd can put in gas tank (can do this later). Start car (a few attempts may be needed)...car will run like shit. Then...the smoke show. White smoke will come billowing out your tailpipe. Drive it good and hard..thats carbon getting cleaned out (take empty can with you in case you get pulled over).After that, drive it about 50-100 miles. Drain and replace oil. Oil will/should be black. That will help clean out any gunk/sludge and the oil pump screen, etc. Put new plugs back in.