Aiming for any amount of pips or percentage each day is fraught with danger. It is best to have a long term average to aim for, but the biggest thing to aim for and to execute perfectly is 100% adherence to your trading plan and money management.
If either is compromised, you will be compromised and will only be in forex for a small amount of time, rather than forex being your instrument of choice for monetary gain.
Yes, I'd love 4% a week, but I hold no pressure to gain it. I lost 8% last week in an unfortunate losing streak that we all have at some stage, but that was capped by money management. I have made half that back this week, however, I am not actually looking at getting my money back as such. I am concentrating on the trading plan and money management. Those thinks alone will move moe forwards. If I get back to my highest equity point (was there before my 8% in losses) this week, next week or next month is not the real issue because it will get there with discipline. Unfortunately, with the current market conditions, my methodology has suffered a bit and not trading as much. I have even gone to trading only "classic" setups from this week to lift the strike rate back up a bit.
Anyway, sorry for all my musings above, but it may prove useful to some.