I just bought my Z that has been sitting for a few years before hand. The necessary parts have been rebuilt but it still has some kinks to work out. In the morning when it is cold, it starts perfectly fine. But after I take it somewhere and it has been running for awhile, when i try to start it up it tries to turn over for a bit and then makes somewhat of a gurgling sound. The guy who worked on it said something about sensors but he is too busy to really help me. Any ideas?