Negative boost at idle
I recently got my car back from the shop where I was having the brakes fixed (new master cylinder & front hoses) & a new fuel filter. A coil was also replaced at the time, as one was found to be bad and was causing a bit of problems. So now the car is running like what I assume it should for an SSEI. I haven't driven one that was in great shape before, so this is based on what it'* driving like now compared to before the repairs. Until now I haven't really paid much attention to any of the gauges other than the temp (its ran a little hot, and just found out that the water pump is going out, so that'* gonna get replaced in a day or two). I noticed that my boost gauge at idle sits below the -10 mark (just like the speedometer at a stop) and doesn't get above 0 unless I really get on it. With normal driving it mostly doesn't get above -5. Now I'm assuming this isn't normal. Where should I start looking for a cause?
On a possibly related note, I noticed that on the front of my boost control solonoid, there is a vacuum plug that had a deteriorated piece of foam on it, no vacuum tube. The plug behind it connected to another plug on the solonoid no more than a couple of inches away. I tried looking for another empty plug where it might connect to, but didn't see any. Covering the plug with my finger didn't seem to make any noticable difference in the engine idle. Is this supposed to connect somewhere else? Is this causing my negative boost?