I have a freind who ran leaded fuel in his ls. what would could this have possibly messed up if he mixed 2 gallons with 5 gallons of premium? I have heard that I will mess up the cat and o2 sensors. any other real damage?

 

no, its only bad for cats and o2's

 

the lead content will plug cat and O2 sensor...........thats why its bad..........you really dont need it unless your boosting high PSI or running very high compression.

 

ok thanks guys

 

it'll also probably have fouled his plugs pretty good..

 

it wont foul plugs too much, i run some mixed in my big block chevy, havent had any probs with plug fouling.