Banger lacking taste, but not cold (4)
I believe the answer is:
heap
'banger' is the definition.
(heap is a kind of automobile)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for heap that I've seen before include "Pile, stack" , "pile-up" , "Mound; old car" , "Mound, stack" , "car on its last legs" .)