The rear O2 (behind the CAT) will have no effect on how the car drives whatsoever. No effect at all.

It'* sole purpose is to determine the effectiveness of the catalyst. Is the cat working or not.

Yeah, I am glad to hear that it'* running better, I could not believe either when I had my lumina that an 02 sensor could make a car run that horrible. I would imagine that the engine computer would not listen to something that is giving the engine such weird information. But, anyways, good to hear it'* running better.

willwren- That'* what I thought. Maybe it'* just something of a fluke, but the car is shifting better, and does not have the rough growl that it had. Also starts up faster. Could be a fluke. I don't know why. Very strange. I was thinking maybe it was sending some weird info to the computer and the computer was screwing up the mixture, but like you said- I didn't think it had any control over the mixture.

I just bought the socket for the front O2 sensor and will do that today. I am on my way to Autozone (Advance did not have any of the gaskets I need in stock) to see if they have the valve cover gaskets, super charger gasket, coolant elbows, and some brake fluid. I am thinking that is what is on the side of the transmission- like I said it'* yellow-ish or light light brown. Not red or black. Fluid in the master doesn't seem to be low though.

Thanks again guys. I've got about 150,000 on it, and I plan on getting another 150,000 out of this thing- or more. Obviously, I don't know everything and probably know very little next to most of you- so your input is very valuable and very much appreciated![/quote]

Hold on a second. If you're going that deep, get the aluminum LIM gaskets. Wait a week if you have to. Then flush the DEX out.

willwren, OK, I hear what you're saying. I probably won't have time this weekend to get the valve covers replaced anyway. Any idea how much the LIM gasket costs? I looked on GMParts direct, but can't seem to find it in their catalog. Thanks.

About 60 bucks from the dealer and 50 bucks from www.intense-racing.com

Buy now, you'll have them by the weekend. In fact, INTENSE has your VC gaskets, too.

You're talking VERY little extra labor to do it all once you have the SC off. You'll also **** yourself when you see the condition of your LIM gaskets due to the DEX (green doesn't do that to them), so wear a diaper or work on the car naked and just let the poop drop.

haha, thanks Wilren. Does Intense sell diapers too?

I have seen the pictures of the LIM, I've known I need to change it. Now just seems like a good time- I'll do the VC, LIM, belts, and I'm even considering the head gaskets. I just figure while I have it apart, I'm half way into the life of the car and they've lasted this long, it'* kind of like insurance- I most likely won't have to do it again. (I know- things go wrong). It would just suck to have it all apart, put and not do something, and then have to tear it apart in 6 months again to do it anyway. It just sucks because I don't have a lot of money, but it'* better spent now than to spend 10X as much later.

I've been trying to break the front o2 sensor loose for the last 40 minutes. It'* really in there good. The engine was warm from a drive, so I sprayed the snot out of it with PB Blaster, and I will let it sit a while and try again.

Thanks again for the help!

Heat-cycling and PB will get the O2 loose eventually. You may need a large crescent wrench for better leverage.

DO NOT CHANGE YOUR HEAD GASKETS. They should last over 500k. I've only seen ONE head gasket here in 5 years and 8000 members that MIGHT have been bad.

The only reason I changed mine is because I ported and polished my cylinder heads. Head gaskets aren't a preventive maintenance item, and should be expected to last the life of the car. You're just as likely to cause problems than prevent any.

INTENSE'* false-knock kit for the trans will work for a diaper. It may hurt when you peel it off, though.

Haha, I will order the intense diaper. I know why they call it intense now- it pulls all your hair out when you take it off.

Ok, good- you just saved me $50 on the head gaskets then. Unless someone else chimes in and makes me think they could be replaced. I know they're not a maint. item, but ....I get over zealous I guess.

I will get the LIM gasket and VC gasket from Intense. I may throw in a 180* T-Stat while I'm at it...it'* only $17 with the gaskets, etc. I'll probably get the Supercharger gasket while I'm there too. Do I use the L67? I never got the L67, L36 numbering.

Wilren, btw- I hate to say it, but my gas mileage has already gone up 0.1 mpg in the little driving I've done on just the rear O2 being changed. Maybe the improved running is in my head, but maybe not....I don't know. Hopefully I'll have the front out tonight and won't be able to test it any further though

Thanks again for the advice.

You would have needed a full set of rocker arm bolts and cylinder head bolts too. That would have hurt worse.

Nobody here will ever tell you to change your head gaskets. You can go to the bank on that.

I'll repeat that the rear O2 has no effect on how the motor runs AT ALL. You changed your cat, right? That'* your gain in mileage, if any.

L67 is supercharged. Happy shopping.