I cut the cats off my 01 gmc 5.3 this weekend and I havent got an engine light yet. Is one suposed to come on? Do I need to get o2 simulators or not since the engine light has not come on?

 

Give it time, it will take a few drive cycles.

 

Not always, I know who people that have been running no cats for 8+months and have not thrown one code yet. But when I did mine, i threw a code within 20 minutes of driving.

 

Its a roll of the dice. My SES came on about 3 hours after I got them cut off. It will probably come on.

 

my ses. is hit or miss. it came on after a couple of drives and then it went out. it seems like every couple of days or so it will come on, stay for the day, and then the next day its off. the light likes to toy with me

 

same here.... its been 5 days since it last came on. Normally mine comes on when i sit at a light or idle for awhile.. if im driving it wont come on

i just clear mine when it pops up... when i get a retune ill get it edited out

 

i still havent thrown a code since the longtubes and ory.