Catalytic Converter

[GUEST]

I have an 07 4Runner with 210,000 miles on it. i suspect there is an issue with my catalytic converter and while driving, the cat temperature banks are different by usually a hundred degrees, but the higher speed I go the difference increases. Sometimes Bank 1 will be up to 1500 and bank 2 will still be around 1250-1350.

Does that mean one of them has gone bad? or is a temperature difference normal?

[carriedi]

1500 is not excessive but it is getting there. Hooking up to a 4 or 5 gas analyzer will give you information about what may be causing the problem. Use a scanner and see what the O2 sensors are doing. check your fuel trims for each bank.

if you have a way to measure the temperature, check the inlet temp. vs the outlet temp. outlet temp. should be 30 to 100 hotter that the inlet. excessive CO can raise the temp to 200 degrees difference front to rear. HC's can raise the temp. differences to 500 degrees.

while 1500 degrees is not toooo high, don't park in any tall dry grass.