[Vwdiesel] Ford Focus problems

[William J Toensing]

I had raised a problem with my Focus on the "Focus Fanatics" website & one of our VW Diesel fans chided me for not bring up the issue on this blog first. Well, this time I will bring it up here first. Yesterday, my Focus started running real ratty surging on & off rapidly when I applied the gas. Then the check engine late came on. Then used my OBD2 reader  & got a code P402 which translated to excessive EGR which suggested I needed a new EGR control valve. However, I then erased the check engine lite & the car now runs fine. I haven't installed this $70 plus EGR valve which I got from our local NAPA auto parts store, so thought I should get an opinion from you people first. 
1) Is it practical to rebuild the old EGR valve & tale the new one back? If not, I may just keep it on the shelf & install it when it acts up again.
2) I have a vacuum leak somewhere when the engine is cold as sometimes, I get a hard brake pedal. The brakes act normal when the engine starts warming up. Anybody got a good idea where to start looking for a leak in the vacuum system? Someone familiar with the Focus might know of a particular weak spot to look. The 2001 Focus ZX3 manual transmission now has 144,200 miles on it & I have owned it since new. I was able to find a vacuum leak on my 1982 Quantum TD. I had laid a trouble lite on the stupid plastic line from the vacuum pump to the power brake unit & it melted a hole in the plastic so well that it looked like the factory meant it to be there.

Bill Toensing, Nevada City, CA