I'm not sure where this post should go but...

I've got an '02 ex cab 4.8 silver w/ 100k miles. My pass cat converter went out and I got 2 Magnaflow high flow cats and a large Magnaflow muffler and basically replaced everything. I had a local Midas do the work. The tech doing the work instilled alot of faith in me when he said that the 4.8, 5.3 and 6.0 were the same...all except the comp chip. I almost packed up and left but I thought....this was a muffler guy..and he didn't really have to know anything automotive to do the job right. Anyway, I got back 6 hours later and as i suspected...the job was fine....BUT when I went to pay the shop foreman told me that they had to put one of their cats in b/c mine was too long (I checked and it was close, but not too long). So, now I have 1 midas cat and 1 magnaflow high flow cat. I didn't have time to argue and I HAD to have my truck back then so I paid and went noting to the midas people that I wasn't happy (they should have called). Anyway, Now I get the check engine light with code P0137....bank 1 o2 sensor 2 voltage low for operating conditions. Its happened multiple times (everyday for 4 days since install, but I have to be in the gas a little to cause it) and bank 1 is the midas cat, and that cat didn't replace the bad cat.

My questions are:
-- is there really a differance between high flow and normal cats (external construction looks very similar)?

-- What could cause code 137?

I just moved and I don't know who to trust around here yet...thanks,

TA69man

 

The high flow cats should flow more cfm but you need the specs for each cat to see what the difference is if any. See if you can get the specs to see how comparable the cats are.

Maybe the O2 sensor behind the cat on Bank 1 is not connected properly or is no good and needs to be replaced. Seems like they fail sometimes after they have been removed and reinstalled. Not really sure but something to consider.

Good luck getting it straightened out.