Losing power, no start, engine idling and there’s oil in spark plugs

I've been having this bakkie since 2006,running OK but now when its cold moves ok. Once it gets hot looses power and water boils,it won't move front or backwards. I'll wait to cool down start it again moves fine but when it gets hot wont move. Temperature gauge does not show that car is boiling.

If l drive a long distance l normally find water in the expansion tank boilin m not sure wat could be the problem

Lately, both when starting and while driving, the acceleration has been absolutely choky. Do the coils have anything to do? Because, in the dark, sparks can be seen escaping when the engine is accelerated. I appreciate your help and time.