ok so my g has 108000 miles on it and check engine light came on a week ago says the cats are below thresh hold. after driving awhile the motor starts to knock not a rob or anything like that and then when i get out of the car i smell rotten eggs. My question is i really dont want to spend 800 on new cats so can i replace them with just test pipes? any info would help thank you

 

Yes you can replace them with test pipes. You will probably need to get non foulers so you don"t throw a CEL.

 

Ok my g has 10800 miles and the cats are starting to smell after i drive for a while.and check engine light is on says here below thresh hold. If i put test pipes on how can i get around e missions?

 

How many miles? Without commas this doesn't make sense! You can go to any automotive shop and have them check your flow to see if your cats are plugged up. Test pipes won't pass regardless of where you live! If you don't live in CA you could get by with high flow cats (HFCs) like BERK'S or F.I. and pickup another 8 rwhp. Cost w/b around $600= but OE cats will cost you far more. HFCs are sold at a good price on our MARKETPLACE under vendor exhaust....Gary