ok this is a good one.
my 92 ls400 has 78,000 miles on it and replaced the air filter,fuel filter and spark plugs and yes i know it really didnt need plugs but i guess i was just bord.
anyway before i done all of this i would get about 210 miles to ahalf a tank with reg unleaded. after it was all done i now get around 160 miles out of ahalf a tank.
i didnt got back with the factory plug i went with the bosch platiuam quaud tip it not a real cheap plug at 5 or 6 $ a peace. what happened ?