Engine management light keeps coming on and gear lever vibrates though revs stay steady car feels "lumpy"

This is on going problem. Three weeks ago engine kept dying and had an egr valve fitted which solved this. Then developed a mis fire in cylinder 2 and had a new coil fitted. Now having the above problem but not every time it is driven. It also had difficulty going up a hill in second gear which it normally does without a problem. Local garage and breakdown service computer does not show a problem. Engine management light came on with all these problems but problem not detected on computer.