Here is what I sent my representatives in D.C. I encourage you to do something similar by going here.
I know you're under a lot of pressure, but consider that any proposed tax increase, no matter how it's labeled or what alleged need it fulfills, is a catalyst for activism -- as you're now witnessing. Your job is to represent the people in your district. They don't want a tax increase. They don't like taxes, period -- it's an American tradition. Can we agree on that? A tax, any tax, is an act of theft, and Americans don't like to be robbed. Government schooling has convinced them that a good citizen must accept some taxation, but they will only tolerate so much.
No amount of political lipstick will make a gas tax hike attractive. The money people are currently "saving" from low gas prices belongs to them, not government bureaucrats. A gas tax hike amounts to nothing less than one more armed hold-up. To repeat: No one likes to be robbed.
Make it clear to your big donors that their money will not replace a large majority of voters.