cwumbs

Bought the car as a non runner with no background history,its an 04 231 with 18601 miles(will come to this later) I've put new coils plugs and leads in and upgraded the starter, new air filter. Engine starts very easily from cold, initially reving to about 1800rpm after 20 secs or so the revs drop to just under 1000. as soon as I touch the throttle it misses/dies- very irratic, it will increase revs to the red line but you have to be gentle on the throttle feeding it in gradually. If its been running for more than about 2 mins it will not restart until cold again. I did a compression test when engine was up to temp using an ordinary compression testing gauge with the non return valve removed and a laser tachometer. 95-98psi on all 6 chambers at 237-248rpm. a bit low I know but as its not been running right for what could be a long time it could have a lot of carbon built up. As the engine warms I can here what sounds like the "marbles in a blender" I've seen described on this site. I've checked the cat, no apparent blockage, I have run the engine without the cat, the marbles noise decreases but that could just be the extra exhaust noise drowning it out and the engine still has the problem.
It appears that someone has had the throttle body apart as the original screws have been replaced with nuts and bolts that are too long. When the ignition is on with the engine off the throttle body emitts a ringing when you get close it sounds similar to r2d2(star wars) speaking, is this correct? I have tested it as per the workshop manual and it was normal.

Getting back to the recorded mileage!!!
When the trip A is displayed the recorded milage is 18601 with 0.0 trip
When the trip b is displayed the recorded milage is 33031 with 0.0 trip
What is going on???
I have connected a diagnostic ecu reader that would only read the chassis number which does corraspond correctly to the chassis, presumably indicating tha the ecu is the original. (as it has at some stage been out!)
Any suggestions on all of the above?.