Welp, was driving the ol Z71 last night, the usual ol driving to a buds house, and I noticed the SES light came on, and never went out. I have good oil pressure, temp is good, voltage good. I cannot, for the life of me find my freakin efilive cable! I have noticed this thing has been SUCKING gas big time, like 11.8mpg highway/city mix. The truck has 101k on it, and seems to be running okay, but not all that impressive as far as performance is concerned, could be because it's 6500+lbs, 4wd, on 33's with 285hp. Anyway, not sure what you all think... Need some tr55's and some wires? O2's? Feedback would be greatly appreciated!

Tony

 

i'd have to say o2 sensor also with that kind of mileage.
bring er to autozone and they will hook up the scanner for free.

 

I'll have to check, but the autozone in Exeter (where i used to live about 20 miles from me now) said it was against CA law now apparently... I'll try the one in Tulare. Buddy and I went halfers on flashscan, maybe I can get him to let me use the cable. This is frustrating. I figured I'd see AT LEAST 15 mpg out of this thing! It's bone *** stock with a flowcrapper and 4" dump, I wouldn't that would decrease the mileage THAT much! I'll check with autozone. Thanks buddy.

 

Yep, Autozone can't do it for free... But they will rent you the equipment and then give you your money back when you return it.

You can probably just give them a credit card, walk to your truck in the lot, read the code, then return it and get your card back... I've done that before.

If you for some reason still haven't gotten it figured out by the weekend after thanksgiving and want to drive up, I'll be out at my mom's place near Kingsburg and can meet up to help you out.

Justin

 

Thanks man, I got flashscan/efilive from my bud, since we went halfers, and plugged it in tonight. It's reading in EfiLive 7.3:
P0430 - Catalyst System Low Efficiency Bank 2
Red EPA
Yellow EPA
Red

Any ideas of a way to determine if it's the o2 doing it, or what?

 

Your driver's side Cat converter isn't functioning as well as the PCM would like to see it. Either that or the rear O2 sensor isn't in good shape.

With 101K miles, it really could be either but I'd suspect the O2 first.

Have you had to smog it recently? If so, how well did it do?

 

Yeah, it passed smog, I just bought it maybe a month and a half ago. I reset it, gonna see if it comes back on. I drove it another 20 or so miles right now after resetting, and it didn't come back. I will check the bank's o2 readings and check for variation.

 

If the connectors are the same and the wiring will reach, you could try swapping the rear 02's side to side and see if the code switches from one bank to the other, if it does, the 02 is the problem. If not, your cat is poop. FWIW, 95% of the time that we've had that code on a Toyota/Lexus, the cat has been the culprit.

 

Not exactly the answer I was lookin for! =( I'll give it a shot, and check it out. Are these cats different than the ones that come on the f-bodies? I have a couple cats I had on my rig that I'll never use.

 

Not sure about that one...but I do know that the cats are part of the y-pipe, so if you wanted to use different ones, you'd have to cut and weld...