Ok, here is the problem. During the day my vacuume is around -460, 0r -450 at idle(18'') according to the PFC. Now thats fine and dandy, but when I shut the car off for a little while then turn it back on, my vac. drops to between -420 to -400(15-16''). Bear in mind the motor is pretty hot from sitting(heat soak). So, of course the fans come on. When the temps get back to normal, the vac. returns to normal. Now, at night, my vac. is at -455, untill I press the breaks and the break lights come on. Then the vac. drops to like -400. Could this be an indication of a battery going bad, or possibly the alternator? This problem started after I put Jacobs spark plug wires on. Oh yeah, my battery is leaking a little. Need to get me an Optima yellow.

 

when you press the brakes or when the fans come on, it takes up some juice from the battery and altenator, thus i figure it would put more load on the motor and the vac. would decrease a tad. i would think that is normal. I'd consider changing the battery however if it's leaking.

danny