I'm trying to get a response from Wengerd tuning because of what happened yesterday. Yesterday I cleared the codes and started it to go to the store 3 miles away. Upon starting there was no check engine light and everything seemed to be normal. Driving to the store I kept a close eye on the vacuum, but it seemed to be about normal for how I was driving. Upon leaving the store when I started it, again no light, but later I was stopped at a stoplight, when the light turned green I did moderate acceleration. Within seconds though the vacuum plummeted and went to 0.0 and the check engine light came on. The car still accelerated smoothly, there were no misfiring, and when I finally quit accelerating the vacuum popped back up to 18. Finished driving home with no repeat.Have you checked the bypass valve hose and functioning?