I am probably going to get some stick for this post, but I need help, and a wise man once told me when I asked him, where do I get answers "we get it, where we can get it"

I have a nissan vanette 2.3 C23H. When driving the van suffers with flatness/spluttering/chugging what ever you want to call it, and smoke bellows from the exhaust. changing gear stops it but when the revs rise the problem returns. I tried getting some live data or even some fault codes but my solus pro doesn't communicate with the vehicle.

I changed the cheapest obvious thing I could think of which was a new fuel filter but rev the engine and the spluttering and smoke continues. as i can't communicate with the car I need some profesional advise