Dkeezer

@DW It's a DBW @BraceMaker 1. No, it doesn't match exactly. But when the idle starts messing up, the speedo has a reading of some sort. 2. No other guages are reading odd. Thanks for your comments

2007 Mastercraft Prostar 197 6.2L engine PerfectPass installed A few weeks ago I noticed my engine starting idling at higher RPM. It normally idles at 600, but would start idling around 1000, then 1200, 1500 and one time it hit 1900. Obviously, this isn't great for the engine as it jolts when I put it into gear. This also coincides with another symptom which may help solve this. My regular speedometer always reads 0mph (driving or not). I bought the boat this way, and it's not an issue for me as I use perfectpass to measure speed. But whenever I have the idling problem, my speedometer starts giving a false reading at the exact same time. For example, when I'm idling properly, my speedo = 0. Then my speedo reads 10mph (when I'm just sitting) and the idle goes up to 1000rpm. It seems like these two items are connected, which could help solve this. Any thoughts?