Thanks I will check it out. I found this article: P1237 fault code, Limp Mode
I tried spraying into the pipe shown, and it started making explosion noise, so i immediately stopped - I have seen in other videos the only noise it makes is the revving sound. Maybe I'm doing something wrong?
Ok, I realised my mistake, I had to wait for the engine to warm up before using the Wynn EGR3. When I did use it, it was making the normal revving noise, after using more than half the can, I took it for a spin. It was definitely driving better reaching better speeds than before, but after a while it went into limp mode again.
I'll continue blasting it later and see if that resolves the issue.