Hey, I recently got a y31 cima too. Like yours, mine was sitting for a few months. Mine splutters on a cold start up, or if I have not started it for 2/3 days. For some reason it only lasts about 5 seconds, when I first turn the ignition. (for these few seconds it sounds like its firing on only some cylinders, but then after just leaving it, all cylinders start working or something and from that point on..it runs perfectly. For me, the problem isnt bad enough to take it in to anyone yet..but I've done some research and Im thinking it might just be bad fuel injectors..which makes sense I suppose. If you google vg30 sputtering, you get quite a few stories about people who have got vg30 engines with injector problems. Maybe get them checked out? I dont know what would be affecting the tacho though..anyway, if you find anything out, let me know cause im pretty curious myself.
