loud knocking NEED HELP!!!

For prolly the past 2 months now my car has been acting very odd. It used to boost at 16 PSI and now it ranges from 10 all the way down to 3. For awhile now when it builds boost it may go to 10 but then drop to 6 and the car jerks really bad. id like to know what that is. Also, my car for the past like 3 weeks has been reading HOT on the temp gauge and yesterday i replaced the thermostat and it went back to normal. Well tonight i was going down the road and it was on HOT again. I pulled over and checked to see if it was actually hot and it didnt seem so. I wasn't gonna chance driving back to college an hour away like that so i headed home and about 3 blocks from my house it shut off. Steam came out under the hood like whoa. I popped the hood and a coolant line had busted so i fixed it quick and started the car. It ran worse than ever. Its puttering around, bogging out, running like a piece of crap. It still wont boost, it jerks around, in putts about and feels like its dead. THe motor was rebuilt i belive about 50,000 miles ago and for some reason my car has no cam positioner and the hole is JB weld shut (should i find on and get it on?) I just need some help so tell me .... UPDATE: i switched the coolant line this morning and started it and let it run for awhiel
it would idle at 1500 rpm and then drop to 800 rpm and repeat. I started down the road and it was driving really shitty. It had nothing to it, it would bog out and sputter unless it was at a high rpm and if it slowed it woudl stall and there is also a REALLY loud knocking or ticking noise from the motor? what may that be?

sounds to me like a fuel pump/filter,and also a rod might be blown from what your explaining im not too sure.as for the over heating......beats me......again,im not sure 1 bit but thats what it sounds like to me,Good Luck

I don't have a lengthy post to give you, since there are a number of things that can cause such problems. It would help though if you listed your car info in your sig, year make model, do it fast before you get hounded. Referring to your username, I would assume you have a tsi.

Exactly how hot was the temperature getting. Though the stock guage is a pretty rough estimate, where was it climbing to? As mentioned, something as simple as a feul filter can fix the drivability, but it sounds like there is a lot more to your problem. That ticking could be lifter tick, which is common among 1g's, if that's what you have. Also if your car was meant to have a CAS on the intake cam, it would have to be there or the car would never run. Hmm, this post did come out to be of some length after all.

the loud knocking noise could be from your lifts by ur cylinders mine was doin that i replaced the one that was knocking and it is fine. what oil do you use?

you might have fucked your motor by running it completely out of coolant and letting it get hot. you could have taken out a rod bearing and the loose rod banging around on the crank would give you the banging noise. in that cause you probably took out the main bearings too. that's probably why you're engine is running like shit too. i wouldn't drive it another inch or even start it up at all until you get it checked out. looks like your motor might get a 2nd re-build.