Missing / running rough

[Cruize]

I noticed the problem when the brake pedal was hard to press and would not go all the way down. If I kept my foot on the pedal and revved the engine, the pedal would then go all the way down under normal pressure.

Til I get the thing home (less than 2 miles), the brakes were operating normal, but the engine was running really rough.

I can't start the engine unless I press down a little on the gas pedal after I start cranking.

I've already pulled each plug wire from the distributor, one wire at a time, restarted it, and it ran even rougher after each wire was pulled.

I had to move it the other day, so in addition to the new starting procedure, I now need to keep revving it to run almost normal.

The Check Engine light is NOT on.

I thought I should be looking for a vacuum leak. Am I right in my thinking, or should I be testing the TPS, MAF, etc.?

Thanks in advance for any help.