recently my 93 850 just barely failed california smog (the hc @15mph was 86 and 85 is max) the car had been sitting undriven for about 2 weeks and i've been told that just by driving for a while could clean out some carbon and lower the numbers. - does this sound correct? a new cat runs about $350, and i dont really want to invest. also, would a throttle body cleaning, new plugs, and rotor help lower hc's, or maybe make it worse? thanks for any help you have.

 

That should make it run cleaner and also change the oil.

 

hey thanks for the speedy reply! a q about oil change - whats your opinion on synth oil - particularly in a car like mine that has just over 100k on it, and probably has never used synth before? thanks again, eric

 

Me I like the synthetic oil.Others will argue about putting it in with the high milage on the engine.