Mysterious Maf Sensor

[oncheap]

ok, some of u know about my dodgey MAF sensor, how it cuts out for 15 min, then i jiggle a connector and then it might work for 3 hours if im lucky. Ok so today i ripped it out and cut the box open to have a look to see if anything was loose inside and if it could be soldered back on. Now there was a copper cover plate that looked liked it had been soldered one before, bit it had come loose, so i fixed that back where it was supposed to be and went for a cruise after 40 min no prob.

can anyone tell me if i fixed anything, or is it just a copper shielding, to cover the circuit board?

ps, i already tried cleaning everything with CO contact cleaner. any help would be great.