Today my 960 started acting funny. I was driving around for about 2 hours this morning. First thing I noticed is that the engine would stumble while waiting for a light. It did this twice on 2 separate occasions. It was a single stumble, not a misfire. Later on it just shut off. No drama, just turned off. It restarted immediately and hadn't done it again for the rest of the trip. The check engine light never came on but I checked for codes anyway, but there werent any. I'd like to rule out the RPM sensor because when the engine did stumble the tach didnt drop straight to zero like I've experienced in the past on my redblocks. It dropped to about 400 rpms. Recently I removed the engine to replace the cyl head and I thoroughly inspected the wiring harness knowing that rub-throughs are common. The harness was in perfect condition. Any idea what might be causing an intermittent problem like this? So far it's only happened at idle, so possibly the IAC?