'96 GT pings over 30 MPH

I've recently acquired a high-mileage '96 GT (calculated 22X,000) from my dad. The chassis and body are in great shape for a '96 that's run through multiple Wisconsin winters, so it needs to be "tuned" up a bit to use as a DD. It starts and idles and revs fine. Sounds fan-freakin-tastic for the miles it has. But once you get in, and get past the "wth is wrong with this thing" tranny, you can drive it almost anyway you'd like under 30 and it seems okay. I'm reading around on the site, and the car goes in to the shop this Friday to be diagnosed, not fixed, so if anyone has any ideas or suggestions to help me save some beans that would be awesome. Basically no maintenance, aside from suspension work and regular oil changes, was done for the last few years of the cars life. So I've come here to try to avoid needlessly dumping money into parts. I'd like to get this done myself, with a little help. Thanks.

Thanks for the reply. On the drive to the shop it was evident that it wasn't pinging. Rate of speed was the only thing changing the noise. It was put on a lift and after "fooling around" it was found that the u-joints were worn through the caps! Thankfully the car was parked and no longer a DD...
So that's been done and now that I've been giving it some TLC it's decided to give me a few love taps (CEL/Codes)... P1443 and P0340 to name a couple. I'll have to do some more digging, but is it possible for a '96 GT, stock aside from a k&n, to have the same issues with the alternator throwing this code? The TSB only shows later years.
Also the exhaust flanges on the x-pipe are rusted and no longer functioning as they should. Is it possible to replace these without a welder? Technically it looks like that's a no, and I could use a welder anyways. The "mechanics" that I've been to lately have only been hacks so I've decided that I am no longer taking my cars to anyone for anything and will be buying tools to that accord... a welder has been on my list for quite some time, but they're costly so if I can avoid it, I will for now. The only temp. solution I have come up with is placing an exhaust, or possibly hose clamps to each end of the pipe with a hose clamp wrapped underneath so that it is being held underneath the clamps on the x-pipe and the one after that so it can then be pulled tight with the hose clamps.. ||_|| <something like that, but it would have 2 hose/worm clamps going along horizontally to keep it together. Same deal as the stock flanges I suppose. Any objections?

Thanks again for the reply, Trinity. YOU RAWK!! Aside from minimal crawl space under the car the u-joints were a cinch even without a press or vice/socket homemade press. Gotta love brass bars and hammers!
Anywho.. I'll look into all those things you mentioned. Great info Thank you. The cam sensor was replaced. With what brand I don't know. Are there any manufacturers to definitely steer away from when it comes to Mustang parts? I've also had a lot of problems with autozone giving me the wrong parts for this '96 GT (3 different parts in a row), and they're 99% of the time better than the surrounding options, is this common or am I down on luck at the moment?
The bit about the exhaust was worded incorrectly. I should have said the exhaust flange CLAMPS are rusted out. The pipes are in great shape with everything intact minus the rusted away clamps. I started it when it was cold so I could visually see if the exhaust leaked at all when the pipes were "connected" by physically pushing them together. Good to go. I was hoping there would be 2-piece option for the clamps though, by which I mean a clamp that is halved so that it can be fit around the pipe without hacking the x-pipe up and having it welded back up. But I haven't found any.