Hello, I have a 100 series 1HZ TD 4.2, best motor ever built by far. The two issues I have are as follows; 1. The taco intermittently (no rime or reason as to when this happens) drops to almost nothing when idling, and then wont read correct when moving, for example will drop down to show 100 rpm, subsequently read ~1600 when doing 100 km, should be closer to 2100. It can go the other way and read way to high as well but a lot less frequently. Checked connections that i can find. 2. I had a service conducted recently, following this, not directly but building, the engine starts to rock the car in idle when the aircon kicks in, say at ~700 - 800rpm. Its like there is a balance issue, the mechanic cant seem to find anything amiss. if i turn the aircon off the RPM's are not enough to make the car shudder, just around the 7 to 800 range. Thanks for any input.