Answer based on context:

Hoping to snap a six-game losing streak the Titans played on home ground for an AFC South rivalry rematch against the Texans. The Titans took the lead after QB Kerry Collins threw a 3 and a 1-yard TD pass to WR Nate Washington and to WR Justin Gage. This was followed by RB Chris Johnson getting an 11-yard TD run. The Texans got on the scoreboard after kicker Neil Rackers made a 37-yard field goal, but the Titans extended their lead after kicker Rob Bironas hit a 30-yard field goal. The lead was narrowed with QB Matt Schaub getting a 12-yard TD pass to WR Andre Johnson, but the Titans would pull away with RB Javon Ringer getting a 7-yard TD run. The lead was narrowed agan with Schaub throwing a 4-yard TD pass to WR Kevin Walter, but the Titans' defense prevented any more scoring chances.

How many total TD pass yards did Collins throw?
4