So, when I first start the car sometimes, fuel pressure is way low. I know this because my AFRs go crazy high like 18 and 19 when they should be about 14, actually much less with WUE at startup. Anyways, I tap on the brakes and the problem magically disappears. So, I'm thinking that maybe the VAC line to the FPR has a slight blockage and a quick tap on the brakes lets loose the blockage so that the FPR can see VAC. I did stupidly bend the vac connector on the FPR a while back when installing the 99 head on my 96 so that I could install the FPR right-side up. Now, I've decided to turn it upside down. Maybe I always had this problem, but have only recently notice with the turbo build requiring an AFR guage. Any thoughts? Blockage, or should the FPR really not be upside down, or should I just replace my FPR? Could it be a vac leak? My vac looks pretty good at about 26 or 27kPa at idle.

 

Uhm...check fuel pressure. FYI, when the FPR sees vacuum, fuel pressure goes down. Well not really down, but it isn't at its max. When the FPR sees atmosphere it will let more pressure build. If you have a MS, which has a MAP sensor, a vacuum leak will do nothing but raise your idle.