Running rich

[whitdog54]

Lately my gas mileage has been somewhat bad.....like 16mpg, my lead foot doesnt help either. When I do get on it, especially WOT, my exhaust smells like rotten eggs. Im not sure if its because I'm running rich or a bad cat, or maybe a combination of both. Im not throwing any codes and i check a/f and the 02 sensors. So what should I do from here? Im thinking I might replace my cat come spring time if it doesnt get any better. So any help would be appreciated.

Its a 00 firebird, with pacesetters, cacto cat, slp exhaust.

[Meatyshells]

Re: Running rich

how did you check your afr and o2 sensors?

[whitdog54]

Re: Running rich

My friend has a scanning tool. Numbers were perfect. But my car smells like rotten eggs when I'm really getting on it, I have no clue why. Im going to change all the 02 sensors, if it still does it, maybe i just got a ****ty cat, it happens sometimes.

[pace2006]

Re: Running rich

How old is the cat? Rotten egg smell typically points to the cat. But also remember that gas mileage tends to go down in colder weather.

[whitdog54]

Re: Running rich

the cat is 5 months old. Car runs like a champ....just the gas mileage and smell is meh

[Meatyshells]

Re: Running rich

im guessing its the 02 sensors

[cam98aro]

Re: Running rich

How old is the cat? Rotten egg smell typically points to the cat. But also remember that gas mileage tends to go down in colder weather.

rotten egg smell can also be caused by a rich condition also.

when i did the intake gasket on my friends car, he had a misfire from a wire being bad and it was shooting raw fuel into the exhaust

smelled horrible

[Richardcoelho]

Re: Running rich

Im pretty sure you have a bad cat,even if the cat was in good shape all it takes is one day of rich running and it will crumble like a cookie:drool: