After replacing the timing chain for the second time, when I press the accelerator pedal it jumps timing and starts running very rough?

It sounds like the timing chain tensioner is not working. Did you replace that as well? I and if so, did you remove the lock pin from it? Here is what I am talking about. Also, did you replace the timing chain guides as well? Please check out the images below to see what I am talking about. Let us know what happens and please upload pictures or videos of the problem so we can see what's going on.