Just had new dual cats put on my baby 1991 trans am gta and the front of cats burn cherry red and one cat is already breaking down with less than 200 miles....305 is modified with 160 thermostat and possible hyperchip as well as headers flowmaster muffler but retains stock dual cat exhaust layout.....mechanic says engine is running lean and cause cats to burn out....any advice you experienced third gen guys would be greatly appreciated! Todd

 

its running really lean or the cats are clogged

 

Thanks! How do you fix leanon a 305 TPI?

 

id check the injector resistence make sure there all pumping what there spose to and remove that mail order chip see if that helps

 

i didnt notice the aftermarket chip. take it out, its probably the problem, they almost always are.

 

Thank you I will do that and let you know!