1987ss

my 99 tahoe gets an average of 11 mpg and i changed,plugs ac delco,cap & rotor, wires,oil & air filter.. i was told but a buddy to add sea foam to tank and some trew vaccuum to break booster? any other suggestions? Thanks

maxwedge

Do it, no harm, may help but don't get your hopes up.

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1987ss

is 11 mpg average?

maxwedge

Stop and start in cold weather depending on driving habits, could be.

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1987ss

would you add it like this? http://members.nuvox.net/~on.roz/cars/z28/seafoam.html

maxwedge

I would not add anything to the oil. Fuel tank, throttle body ok, thru the vacuum ok.

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1987ss

thanks