Yep. Need to pre-cat O2, as it has a great influence on how your truck runs. (no non-foulers on that one.) Need the post cat O2, just so it doesn't **** off the PCM... (non-foulers on this one). You can buy weld-on bungs for dirt cheap.

 

Just keep the part of your stock exhaust that has the Post cat O2 socket, use the foulers in that. Unfortunately the pre-cat O2 kind of screws into the cat where the Y pipe meets, so yes, for that one you'll need to drill a hole for it.

 

Ugg. I don't weld.......yet.

 

Jegs and summit both offer an 'off road' y-pipe, that has no cat, both O2 bungs, and flows a LOT better than the stock stuff. 200 bucks and some change though.... has the advantage of being a direct bolt-on.

 

Thanks HeyYou. Funny thing ia, I was trying to get around the $200 replacement cat cost. Lol. And understanding that a staight pipe back would gain the most with a new Y.

 

Here it is. 145 bucks...... Still not exactly cheap.

 

You....are DA MAN! Always full of help. Thanks, bud! I think this is the best options for getting the most out of the truck (for those of us not in a non-attainment area that requires emissions testing).

So my understanding is that I could buy this off-road y-pipe and install the existing front (upstream) CO2 probe and then install the existing back (downstream) probe with a fouler. This should solve the clogged cat issue and provide more HP to the road than with a free-flow cat, and cost $50 less.

 

Almost right, you need 2 foulers for the downstream O2. the idea is basically to have the sensor still there, but out of the direct exhaust stream.

Refer to this video, its a completely different vehicle, but same idea.

http://www.youtube.com/watch?v=KnYUHwTxKkE

On every other point, you are correct sir!

 

Went out and tried to pull the upstream O2 sensor. Man, that thing is really snug. My little 8" pipe wrench and hammer didn't budge it. So I hit it with some PB Blaster (not planning on driving anywhere, any time soon) and smash on it again. If that doesn't work, then I will buy a 7/8" box wrench and put some extra torque on it with a breaker bar through the closed end of the box wrench. Can't see how you would have enough room to get on top of the O2 sensor tool with the Tranny pan right there.

 

7/8th wrench is your best bet, you can also try starting the truck up for 2-3 minutes to warm up the exhaust system a bit, thats what worked for me, that and alot of elbow grease.