yup what ohsofly said does not apply to you since your engine is throttle body injected, those "valves'' are your fuel injectors. he was talking about the vin w engine wich has the spider injectors.

 

what you need to do is go test drive the car and try and remember every detail so you can come and tell us if not were shooting in the dark

 

Alright, here's everything I can tell you right now.

On start up, everything is fine. It starts quickly and strong, revs high for a few seconds, then lowers.

Driving, I can still hear my exhaust leak, though barely. I attribute the quieting out to the engine smoothing out with the addition of the cylinder that wasn't firing before. The whole truck is actually quieter, at idle, driving, etc. I do develop a bit of a stumble at cooler temps, and at a constant, consistent throttle. Say I put it on cruise control, that's when I find it most prominent during a normal drive aside from cool temps.

The codes are still throwing, usually ten minutes or so into a drive. I also haven't reset them again, but they haven't gone away, either. I get a pretty distinct smell once I shut her down, I can't really place it, it's like gasoline, exhaust, and hot metal all at once. That throws a red flag in my head that says not good.

I put 20 in it today for gas, and just judging from what I can usually tell from my gas gauge as two gallons, I'm getting about 12 to the gallon. Which, I came down from 17 in the first place. I'm filling it tomorrow, and will have a solid number the next time I fill up.

Anything else I should include?

 

The heat & smell comment (like a hot, metallic acidic kind of smell?) & crappy mileage leads me to think of 02 sensor/s &/or the cat.
If you get under the vehicle & hit the cat, does it rattle? Just use the heal of your hand & keep your face from under it - crap/debris will fall.
What codes are showing now?

 

The o2 sensor isn't but 4 or 5 weeks old, i sure hpe nothing's wrong with it, it was a bitch to put on. I can check the codes again in the morning, but on last pull (after plug and air filter) was still 13 and 44. I think 13 was still there, at least.

I don't know about the cat, but in my opinion, they're useless. I may as well have it straight piped through if it's the issue, I don't have inspection where i live. But, I have one O2 sensor, upstream of the cat.

 

I'm not sure how many 02 sensors are on a 1st gen but I do know that an exhaust leak (depending on the size of it) can effect an 02 sensor.
Might not be the sensor but the wiring or connection. Was the plug clean, no corrosion, dirt etc? The wires are around the exhaust & we all know they get freaking hot. The wires may have gotten burnt, chafed anywhere along their route. Trace the 02 sensor/s wiring just to make sure & or grab a multi meter & check continuity along the wires. <--- It's a bitch, I know. Tracing wires & testing is a PITA. But any break inside the insulation could cause intermittent issues. That I know from my blazer dying at random times due to a wire broken inside the insulation that lead to the ECM.
BTW I'm not saying any of this IS the cause of your grief, just things I'd look into. ;-)

 

I've only got that one, spent a lot of time searching for others because the guy at oreilly's told me I had 4 because he was looking at a fullsize blazer and not mine.

Definitely right on the o2 and exhaust leak thing, but, i don't know much except that it tells you about lean or rich and flow. There's not much of a leak now, but I would like to get it all fixed. I'm going to my usual guy one I get paid to see what he can do for me.

 

Rich or lean causes a lot of different issues or ways the engine runs. A cold engine runs rich to warm up & vice versa. If the 02 sensor or wiring to it is faulty it could be telling the engine HEY we're not getting enough gas, pump it up a bit, we're too lean. While the engine is actually warm & that could lead to your crappy mileage, off smell when you shut it down etc.
How is the coolant temp on a regular drive (a trip you've done before, close conditions etc)?

 

Temp seems good, stockg gauges could be pretty decieving I suppose, but it's usually within a normal range. Now that you've brought it up, I'll pay more attention to it tomorrow on the drive to school.

 

Is your exhaust leak before your o2? If so then it would be showing a constant lean condition which the computer would try to make up with by raising the long term ft into a rich command, but once it's out of fuel control it would show a code for o2 constant lean condition. After that it's just going to be in limp in mode. So if it is before the oxygen sensor then you need to get it fully plugged up.