I have used Seafoam in both my fuel system, air intake and oil. I bought three bottles from Wal-Mart, their $5 a bottle, rather than $10 a bottle at Pep Boys. I ran one bottle in the gas, and others before I would agree the seafoam in the oil and run your car for about 100 miles and it will clean up a lot of sludge deposits in your engine it did to my engine @ 85,000. Also, i bought a empty spray bottle to spray the Seafoam in the intake manifold and the vacuum tube to the IAC and the car is running as if it was a new one.
