Have been trying to diagnose a rich idle problem this evening and I worked my way to my Sard FPR. Checked vacuum lines for any tears or cuts (didn't see any from first glance), and then set to work on checking the fuel pressure. Pulled the vacuum line off and surprisingly the fuel pressure jumped up to about 50psi (it should be 42.5psi on the early Evos). Thought I'd found my problem so I blocked the vacuum line with my thumb, loosened the locking nut and turned the adjusting nut anticlockwise. Pressure dropped to 45psi, but then wouldn't drop any further. I even removed the top elbow fitting that the vacuum line would go into and it still wouldn't drop below 45psi.

So I thought "What the hell..." and decided 45psi was good for now, so I tightened up the locking nut. Put the vacuum hose on and watched for the fuel pressure to drop as it should do. But there was absolutely no movement in the fuel pressure needle when the hose was connected.

Any ideas? Am thinking either the FPR has a problem with it or I'm just inept and there's a big vacuum leak somewhere along the line.