missfire, help needed

[gplategt]

hi ive a 2001 20vt awt code its been going fine for a while but the management light pops up every know and then with fuel trim system bank too lean, i clear it then its fine, i done plugs oil and oil filter and fuel filter. today i cleared the code and it started misfiring on cylinder 1 and 2 , then a few codes popped up, multi missfire, lambda circuit malfunction , and supply voltage 30 too low, has any one had any of these before and what was the root of the problem