BF XT misses and struggles up hills misses slightly on idle. Check engine light on. Code : running lean

Car has liquid injection and petrol

Does on both petrol and gas. (Worse on gas) Mainly noticeable on steep hills. Will also stall very occasionally once slowed to a almost complete stop

Ive also noticed I seem to be using some petrol also when im on gas. But im also using gas. Unsure if its In my head or not but I believe it could be using petrol also (slight amounts) when its on gas.

gas system has 3 liquid injectors. It is a sprintgas system.
car appears to not miss under WOT mainly noticeable when trying to hold revs at a certain point or maintain a speed

148xxx

Ideas?