Serious problems with 98 v6...Rough/Hot...Misfiring or Injectors maybe?

First let me say I'm still kinda new to the DIY world, but I do know enough to do some regular repairs.

I'm having a number of problems with my Automatic 98 v6... Don't have access to my codekey now but I know I've had P1150-P1152 all at the same time (Rich, Lean, and System at limit?) and an O2 sensor problem (forgot what sensor and bank) recently.

Just a few months ago I had my radiator and fan replaced by a guy I know pretty well that co-owns an automotive shop and soon after I did the thermostat myself (think I went with a 180). After getting the air bubbles out of the coolant line my car ran fine and temp was pegged at the middle of the gauge no matter how hard I drove the car. Also recently replaced spark plugs and wires after I got a code for a misfire, and everything was fine after that.

Problems:
--A few days ago it started getting hot again and trying to run the defroster or hot air yields only cool air (seems like thermostat, but I tested it in boiling water and its fine).
--On startup before putting the car in drive, I get a ton of white smoke coming out of the exhaust (even when the car is at normal temp).
--Just this morning, idle was very rough and sat around 650RPM (very low for my car, its normally about 800)
--Driving the car was extremely rough, as if having a serious misfire problem (very bumpy, acceleration slower than normal, and sounded very raspy). The check engine light began blinking instead of just staying on.

If it helps with info, I have a few mods: AmericanMuscle.com CAI, BBK TB, and BBK Underdrive Pulley Kit (2 piece).

I know I may need one or more new injectors, but I don't think that can be 100% of the problem. Anyone have any ideas?

While I'm thinking about it, anyone know the flow for the stock fuel injectors on a 98 v6? I found a cheap set of 6 but they're 19lb and idk what (if anything) that would do to my car. Thanks!

There is a pretty good dip at the end of my driveway that holds water and I know could soak the undercarriage, so I'll try to dry it out to see if that could be the case. Being from F.M., I'm sure you know how often it rains here in S. Florida (Raining where I am right now!), so the dip has been a puddle for a few days. Hopefully its that easy but if not...:/

Leaks are not what I wished to hear lol, but I won't "shoot the messenger", so thank you for the all of the detailed info. Sometimes the real problem is just unavoidable. That would seem to explain a lot of symptoms in one common problem. The cars odometer actually stopped working which wasn't a huge deal for me (and I believe its still legal here if I just drive with it and don't try to sell/trade it without notification that its not working). Given the pace that I was driving it in the first year or so I had it, I'd be right at or just above 160k miles, maybe 165k...