Water in intake

I have a 2005 focus ZX4, started hesitating and almost stalling on take off then check engine light came on. Only seemed to happen in wet road conditions. Checked the code, was p0103 MAF circuit high input. Took it in to have it checked out and the sensor replaced, found that water is getting into air box. They replaced the sensor and said they fixed the problem and that it wouldn't happen again. The next day it died on the highway and was doing the same thing as before, but with no check engine light. Has anyone heard of this problem or have an idea how water is getting in?

I've never heard of this problem. On the Escort (Predecessor of the Focus) the intake box air inlet is inside the front of the left wheel well. Due to it's position it is not prone to water getting in there. The Focus may be different. I would stay away from deep puddles in the roadway. The MAF would read high input if it got wet. The MAF is fairly expensive on the Escort and I would think on the Focus, too. Sooooo. Take it back. Make some noise. The squeaky wheel gets the grease.