Bigvic

Alright first off, the engine is not an LS1, but it is LS1 based. It is the 4.8 in my wife's 02 Tahoe. She has approx. 50K on the engine, and now we have a SES code. Two to be exact. Sometimes the light will stay on for a few days then might go off for a week or two. I had autozone pull the codes and although I don't remember the exact code numbers, I do remember the descriptions. In a nutshell it said that both the right and left banks of the engine were not running efficiently (one code for each side).

Now my thoughts on the situation are maybe bad cats or O2's, but what are the chances that either one of those would go out on both sides of the engine at the same time? So then I think maybe it could be the maf? I did put a K&N filter in it a while back, maybe I over oiled it and got oil on the maf element, but the filter doesn't look over oiled.

When we bought it we did get the extended warranty, but each visit now costs us $100 since the expiration of the original warranty, so I would like to be able to fix the problem myself for under a $100 if it is possible. Now I know that just by reading my post it will be difficult to diagnose this problem, but if you guys could give me some ideas on what to check out that may be the problem, I would really appreciate it.

Also, when the SES is on, the engine runs the same, however I don't know if gas consumption has changed or not.

Classic Style

Do you have any idea if it is the Cats? Perhaps it is spark plugs. If you could post the codes, that would be really helpfull.

If you can, I would start with spark plugs, check their condition/gap, if that checks out, see if your MAF is dirty/coated in junk. That should be giving you an incorrect voltage code however.

When the MIL (SES Light) is lighted, and you listen to the engine, do you hear any tapping, or clicking that might indicate a misfire condition?
Hope that helps.
___________
Classic Style
LS1 Powered Porsche 911 (in the making)

Bigvic

Well I changed the plugs last weekend, but that didn't change things. At least that didn't remove the code. If the plugs were the culprit, would I have to remove the code or would it do it on its own?

I will check out the maf when she gets home later tonight.

As far as the cats are concerned, how would I know if they were bad?

blk~2000~Z28

Was it any of these? There are other codes like "insufficient" could it have been one of those?

P0430 - Catalyst System Low Efficiency Bank 2
P0431 - Warm Up Catalyst Efficiency Below Threshold (Bank 2)
P0432 - Main TWC Efficiency Bank 2 Below Threshold
P0433 - Heated TWC Efficiency Bank 2 Below Threshold
P0420 - Catalyst System Efficiency Below Threshold (Bank 1)
P0421 - Warm Up Catalyst Efficiency Below Threshold (Bank 1)
P0422 - Main TWC Efficiency Bank 1 Below Threshold
P0423 - Heated TWC Efficiency Bank 1 Below Threshold
P0424 - Heated TWC Temperature Bank 1 Below Threshold

Bigvic

Okay, I went and had the codes scannned today. The guy said that it was a PO430. He said that that code showed up twice. Right off the bat he said it was my O2s, but I wanted to check with you guys first.

Thanks,
Victor

davidWS-6

iTrader: (13)

i threw that exact same code po430 last week had it cleared at autozone and showed back up today. im wonderin if anyone has a answer myself ?

svtwhat?

iTrader: (17)

we had that code on the 99 and it turned out to be a dead o2 sensor

2xLS1

iTrader: (25)

You have a bad passenger side cat that is still covered under the original GM warranty for 8 years or 80000 miles.