Are you positive the aux water pump works? Has the servo been upgraded?

An amplifier will go bad, if the aux pump freezes and it is advised to change it with the servo unit....

You need to replace the sensor tube, with out that tube....the system cannot sample the air....

Go to home depot and buy pipe insulation hose, in the plumbing section......glue the slit closed....cut to length and replace the tube...

If your have a vacuum leak in the system, you must find it....and technically it won't be easy...

First check all the vacuum hoses that run along the fender under the battery tray....that is usually where a leak will be found....

Next is to test all the vacuum pods under the dash.....remove both knee panels and you can see them all....use a vacuum pump like a mity vac and see if they all hold vacuum...

And start reading this....

http://www.imperialclub.com/Repair/Lit/Master/281/cover.htm

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