man you are dealing with allot of issues.
can't help with the oil in coolant. i never saw that with my car, which just happens to have been overheated bad by a family member
lots of pressure in the coolant system but I'm seeing no oil. Does your car have the oil cooler/coolant exchanger like my turbo diesel does? Perhaps that is breached?
I would not have let the waste oil touch the car until you got things ironed out. Speaking from experience your injection pump could very well be clogged up. I had the same thing happen during an experiment with a cocktail and it sitting. Car barely turned over and I had to do 2 soakings of atf for a day each before it would fire up on its own again.
I broke that pump down a couple weeks later and found gunk attached to body walls and also the vanes. So much gunk was in the way I couldn't spin the plate with just my hand without binding. I don't even understand why it was running as good as it was at that point.
My car has been plagued with some kind of restrictions that would draw fuel from the tank when off. So every cold start it had to purghe itself then run rough for a bit until it cleared itself out and then would run like normal. Ended up running new lines all the way back to the tank, blowing lines out, and resealing my pump. It got getter but there always seemed to be a bubble hanging out at the inlet.
Every pump I have come across used thus far has reacted to the cold start lever so that doesn't seem good. If your engine was so clackity to begin with perhaps you wouldn't notice a difference but if its that loud I doubt you would running it, since it would sound like somebody hitting the engine with hammers.
Here is another wierd one. A few months ago I decided to mess with my lda on my pump to clear some off boost smoke. I had messed with things and found fuel underneath, not enough to come out vent but it would be there after running. Now literally this is all I did and when I went to drive the car the wierdest thing happened. Car would start but within 5 minutes the idle would drop until reving it the car would not return to idle and die. Ended up using an electric pump, fuel from a jug, new filter, etc. and it persisted. One time while reving the return line blew up like a baloon and bursted off and then the fuel shot back through the inlet.
I was baffled, yanked my pump off the car and cleaned and resealed everything just to confirm. Everything seemed correct, in relation, no buildup or burn marks, etc.
I put the pump back together, retimed it and it has been working since, BUT I ended up having to turn the fuel in just a bit to get a new baseline for idling. This fuel screw was still staked! The only thing I noticed at the time was that the governor arm where it was indexed was in its slot when I pulled the lid, but wasn't turned to the side to lock into that tab? Did it move, did it not go together when resealed many months before I have no clue.
Now with my crazy pump the car would die just down the block like 10 times and not restart hot, it was really wierd. I assumed restriction but I ran all the lines into a bucket in the front seat with a new filter. You make it sound like it will rev out atleast.
Only time I have seen that crazy kind of bucking and non responsiveness from the pump is when big air bubbles are at the inlet and the car is about to die. You definately need to have some clear hose in the engine bay from a bucket on both sides with a new filter to start fresh and troubleshoot from the get go.
I installed a china fuel filter that I purged in a bucket and it was causing crazy restrictions from the get go I couldn't believe it.