Quite honestly I can't say for sure if the tach dropped to 0 prior to the stall or not while driving. I was usually looking at something else or it happened after i looked away from it. The times i was sitting in the car with it at idle with the scanner hooked up, the tach (dash) was fine and fluctuated with the stumble condition but didn't 0 until the engine was stalled. At restarts it zero's out and moves immediately upward with idle rpm like normal. I didn't mention this in my original post but I also don't have any surging or runaway idle like you might expect with a traditional air side intake leak; it has only minimal fluctuations (unnoticeable) in rpm typical of every can I've ever owned. The engine behaves as if there is truly nothing wrong until it stumbles or stalls. I'm cornfused.
