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Ok so for the first time since I ran this pig into a pond, I have been driving around free and clear of engine lights and vehicle problems. Until tonight.
This morning when I got to work (say 18 minutes of 80% highway driving) when I got out of my truck I smelled exhaust. I mean, I felt like I was pinned under the tail pipe...

Tonight on my drive home, it was running fine all the way up until i exited the highway. At idle, in gear, with the brake depressed, it felt a bit weak. When I left the light, the engine felt like it was slightly bogged down then with a light surge, popped back to normal all the way through first gear. At 3200 rpms or so, I dropped into 2nd and BLAM! problem time...

2nd Gear was horrible, tach dropped to 1000 rpm, acceleration crapped out, and my oil pressure dropped to in the 30's... I pushed through until it popped into 3rd and things were mostly normal again.... At the next light, i could smell heavy exhaust again, and the initial acceleration bog-dow and surge happened but this time the oil jumped from 35-ish to 50-ish when the rpms popped up.

I looked into a number of rough idle, and surging/bogging threads and here is what i have so far: (all less than a year old, most newer)
New cap/rotor/plugs/wire, cleaned ERG and installed screened gasket, cleaned feul tank, new fuel filter, seafoamed through throttle body, cleaned throttle body, cleaned MAF sensor, changed OEM air intake with CAI and cone filter.

Last time it was in, she had the following codes:
P0147 - o2 Heater Circuit (B1/S3)
P0300 - Random Misfire
P0446 - Evap Vent Control Sucks
P0463 - Fuel Level Sensor

The searches showed to following common problems: Dirty IAC, Bad Air Filter/Improper Install, Plugged injuctor/bad Spider, Dirty MAF, TPS out of whack, Plugged EIP Screen, and (overall) bad distributor....

I would have to crack her open and see, but I was leaning toward the distributor/EIP UNTIL you factor in the exhaust smell....

I am down and out again boys. I call upon your expertise yet again

I am still searching and will update if I turn anything up. I do NOT have the code for what ever tripped the SES light tonight. Will pull that tomorrow.

Initial guess: Squirrel in my tail pipe

 

I would take a close look at your catalytic converter.

If you have an infrared thermometer, you can take it for a spin and get the exhaust good and hot. Read the temperature ahead of the cat and behind the cat. There shouldn't be a huge difference if the exhaust system is up to temperature. The inlet shouldn't be as hot as the main body of the cat either. This is just theory at this point since I haven't actually tried it, but it is something to try without taking things apart. I'd have to take a look at my temps to get a baseline. Maybe someone with a properly functioning s-series truck could do the same.

 

Interesting. I had a bunch of water in my exhaust pipes when it sat underwater for a few hours. They dropped the pipes and drained it. Haven't had a problem with exhaust smell in the past year, but that would make sense that it would have plugged it up or at least sped up the plugging process.
Do you think a Autozone-style auto place would have one I can borrow while pulling my codes? If so I can do that at the same time I read the OBDII. I like the idea of a diagnosis without tearing things up yet
I guess my squirrel guess wasn't TOO far off after all.

 

**UPDATE**
So I went to Autozone and after being told a bunch of crap about not be able to let a customer use a scan tool in the parking lot anymore due to theft (I'M IN GOD DAMN UNIFORM and tomoorow is F-ing Veteran's Day!?) I struggled out of the parking lot wishing I could burn out and spit tire goo all over their window. i went up the street to a local muffler shop and ran through the song and dance of what was wrong and what I had done so far. As for the initial guess: Plugged Cat (thats 2!) but after pulling the codes, the muffler jockey said he no longer felt that way and suggested i go to a dealer, but bring back the work order and he'd beat it by 10%. Weak...

Codes:
P0410: secondary air injection system
P0300: random FAIL!

Newly noticed symptoms: Exhaust smells HEAVY, rich, thick.
I burned just under 1/4 tank of gas going 13 miles
When Just after i let off the gas, instead of just revving down, the RPMS hold for a half second, then there is a high pitched whine like a turbo on a diesel engine, before it drops down as normal.
after red lining it 4-6 times to try to get over 55 (speed limit was 60) there was a noticeable drop in power followed by smooth acceleration and normal power for all of 3 miles before symptoms returned.
It is not as bad (other than exhaust smell) when cold (closed loop) but very strong after warming up (open loop).
No more Oil pressure fluxuation today (woot!)
Noticed red dusty build up (like fried clutch dust) around my EGR valve, but not on gasket or engine side, just valve side... (?)

I bought new plugs, wires, cap, and rotor. I opted not to just buy an air pump to throw at it, and am starting to think I will be returning the afore mentioned gear. I went outside and popped the hood to mist down my wires, but while staring dejectedly at my engine, I noticed a light sucking sound. Found a split vac line. the one that bridges the gap from the T just behind the fuse block over to the T just behind the throttle body/in front of the distributor.
I will grab a new one tomorrow morning and toss it on HOPEFULLY that will plug up the leak and might just buy me a pass on the P0410 thing...

Still doesnt explain the P0300 and exhaust smell though

 

**UPDATE**
I installed the plugs, wires, cap, and rotor today. When I pulled the passenger side, all from that bank (2, 4, & 6) were black. That whole side is running rich.
Driver's side was all perfect though. Pristene. Textbook even. So that leads me to believe I may have an O2 sensor gone wrong. Would explain the plugs but not the exhaust smell still. Running that rich on one side would explain the exhaust smell... but not the air problem (P0410),
After changing out the vac line, my codes dissapeared (w00t) but it still ran like hammered crap. After putting the new parts in it idled high (1000 rpms) for a few minutes then drove like a champ.... until it got warm....then SES blicked a few times and kicked on.
Also used another 1/4 tank going 16.7 miles today. that puts me at 1/2 tank for 29.7 miles.... thats a little better than 3 mpg. Still better than the M1A2 Main Battle Tank @ .6 MPG... but not by much.

New Symtpoms
Runs at higher rpm than normal (2200 rpm at about 50 mph with my foot OFF the gas...)
Eletronic buzz (like fuel pump spinning up) is now a CONSTANT sound at idle.
After throwing what ever codes came back, my OBD wont talk to a scan tool any more. Could just be that it doesnt want cheap scan tools plugged into it, but this is new.
Struggles to get into overdrive. I had to stomp the gas and let it rev up to red line before it would kick into OD and pick up to a whopping 70 MPH...

Does any of that spark anything from anyone? Possible avenues to look into? Anything at all?

 

Do you have an exhaust leak on the passenger side?

Have you observed the O2 sensor output from the B2S1 sensor?

 

No idea yet. I will crawl under and check for a leak tonight after work. I also have not scanned the O2 sensor since I only started leaning that way after pulling the old plugs.

Exhaust leak would explain exhaust smell. Exhaust leak would explain the crappy acceleration at temp. It would also cover the exhaust sounds/loss of power.
It would not explain the P0300 missfires though. Unless there is a leak at the header right? The O2 sensor would not cover the exhaust leak, but it could be both going out at once.
God, I'm glad I found this forum. Kyle, thanks for entertaining my problems

BONUS: Check engine light went out and the vehicle ran like a champ on my way to work this morning. Then, surprise, when I exited the highway, she stalled at the off ramp, started up and limped to work running 4k rpms at 30 mphs.... BOO!

 

Sounds more like you have a problem with the passenger side O2 sensor and/or wiring then.

The reason for the exhaust leak thought is that if the exhaust were leaking before or even slightly behind the O2 sensor, it can allow outside air (laden with O2) into the exhaust and skew the O2 sensor readings making the PCM think that bank was running lean. If bank 2 were actually running way rich, misfires can definitely result.

You know that bank 2 is running rich as evident by the coked up spark plugs. You just have to figure out why now.

 

**UPDATE** So today the Army paid me to crawl under my vehicle and throughly check my exhast system. Turns out you were right Kyle (surprise, right?)

At the front Cat I found a sizable crack in the weld on the inside near the top. maybe 3/4" long. Feeling slightly more optomistic, I limped back to the muffler guy. LONG story short, I had him throw it on a lift and check for exhaust leaks (instead of just OBD-ing it). BLAM! Plugged front cat. After window shopping for a shiney new cat, he chopped the old one out, and cut in half. The (i cant remeber the name) honeycomb looking crap was meltd, ashy, and blackened. I guess 10 years, 176k miles, and a few hours full of water will do that to you...

While he was in there (and seeing the condition of the front) he dropped the second and it was just as screwed (didn't chop it in half though). So after shopping a bit more, i found a nice looking Magnaflow Performance high-flow that fit ever so right. A newly bent connector (between the two) and i was on my way. The shop wanted $150 for EACH OEM O2 sensor installed (WTF?!) So i borrowed the tech's truck, ran to Car Quest, scored 3 sensors for $150 total, gave the tech $20, and had them installed free

Here's the sucky part. Car runs WORSE now... why?! How!? Well the original offending O2 sensor: P side coming off the header, is frozen solid. the dude said (after hitting it with a torch and PB blaster like 4 good times, said I would need a new hole (bung, bong <-- ?) since the O2 was striping out the threading. BUT it was already 45 minutes after closing and I was less then a mile from home. So I struggled home, and will dose her with PB before I take off for the weekend. Hopefully that gets some pentration action and helps free up the O2 sensor.I wil bring it back monday nigth and they finish the job.

If, in a perfect world, all goes right..... I should be able to soak it this weekend, and have the new hole done up (welded on, milled in, i dunno) and the last new O2 plugged in. That would put me at: 7 wires, 6 plugs, 1 cap, 1 rotor, 2 cats, 3 sensor, and a sizable dent in the old bank roll.... only time will tell....

On a side note: Whats a good price for 2 cats and 3 O2's + labor installed? (not universal crap, all direct fit parts)

 

I hope you didn't waste your money on those O2 sensors. $150 each is WAY too much, but AC Delco sensors are not that cheap either. I have tested a number of aftermarket brands in a few different GM vehicles and was never happy with the activity of these new sensors. The AC Delco sensors I have tested side by side were much more active out of the box.

Unplug the passenger side sensor NOW. DO NOT continue to run with the bad sensor installed. It is very likely that the over fueling that was occurring on the passenger side is what melted the cats. If it continues, you could melt down the new cat as well.

Check your plugs often. If they continue to show signs of over fueling, you need to figure out where the extra fuel is coming from. This is especially true if the O2 sensor is unplugged. The PCM will go to a default fuel map for the passenger side which should be conservative.