Chad, If you want to be sure that your bad booster is causing that rough idle..with the engine running,remove the booster-vacuum hose from the intake manifold,(I believe it attaches to the rear passengers side intake port)then cover where the hose attached with your thumb. Boosters? I got one for my '75 about 9 years ago,from Cardone. It came with a master cylinder. I believe that finding a booster for a '74-5 would be harder than finding one for a '73 since the '74-5 Imps had 4 wheel disc...and not many were made. My skip turned out to be the booster,but my brakes acted normally. First I thought I had a bad plug,then wire..then did a compression check (checked OK)...took off the carb and checked for a mouse-blocked intake port.... I even took off the valve cover in thinking that a valve wasn't opening. Finally I unhooked the booster hose and plugged the hole in the manifold. Voilla!! I shoulda checked the easiest thing to check,first. Steve from Albany,N.Y. '75 Imp 4dr <--got a new,freshly painted,black booster and master cyl 9 years/10,000 miles ago. No probs with it. '79 440 powered 35 ft RV <--the master faces backwards near the left front tire. ________________________________________________________________________ ----Original Message Follows---- From: Chad Zeilenga <chadzeilenga@xxxxxxxxx> Subject: IML: Power Brake Booster on 73 Imperial Date: Sun, 20 Jan 2002 12:45:39 -0800 (PST) Well I beleive that I have found the culprit of my rough engine idle. The other day on the way to work I could hear a slight hiss as I depressed the brake pedal. This led to a very hard pedal and practiacally manual brakes. I took a look at the booster and where it enters the firewall. I believe that the diaphram is bad. Does anyone know of a good place to get a good rebuilt booster? I have heard of Booster Dewey, anyone else? Chad Zeilenga 1973 Imp 1966 Galaxie 500XL _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp.