[josephvman]

My 3.2 Targa has an intermittent surging idle. I had it at my local air-cooled specialist a couple months ago, and they couldn't get it to duplicate the issue when they had it. They checked the usual things like vacuum leaks and idle control valve (I pulled that myself prior and it was working fine). A couple of times since I got it back the car has died when clutching to a stop, but for the most part other than some bouncing idle at cold start maybe half the time, the car runs great under throttle and after running for a couple of minutes it idles smoothly.

A couple of days ago the tach started operating intermittently. It either doesn't move or it moves wildly, but about half the time it works normally. It went dead a few years ago and we sent it to Palo Alto Speedometer for repair and it has been fine since.

Car has a SW chip, M&K cat bypass pipe and sport exhaust. Any chance the surging idle and the tach are both caused by an ECU issue, or somehow related?