If a target marketing campaign was performed targeting low and moderate income census tracts in order to increase numbers in these areas for CRA performance data would this be a problem?

I'm going to say no, because you are not using a prohibited basis for excluding census tracts.

Well I know if you targeted upper income it could have a disparate impact.

The logic behind that is you are in theory "hurting" a protected class by targeting only upper income census tracts. Upper income people tend to not be a majority of protected classes, while the areas you would be avoiding lending would be made up of more protected classes.

In this ones case you are discriminating (which is probably OK), against non protected classes. Many financial institutions engage in programs designed to help their CRA by targeting L to I census tracts.