Well yesterday and up untill then it was fine. All that was done since then is that I took a compression test last night. Today when I was leaving to go to work , the needle wouldent go past 1k, everything else seems normal just the tach has gone bonkers. My Question is , is there a contact that could have gotten wet when I was driving in the rain yesterday, or was croded and is giving out? Or is this just that the car is about 30 years old the tach needs to be replaced. If you can shed anny light on this please do. Thanks Gary Portland PS has annyone installed a tach from a later 280 ,if so what year do you recommend and any advise will certanly be apriciated thanks ..