Hi! Lately, when first started, the (cold 30-40F outside air) engine idles very roughly. It will also miss fire occasionally. Just about the time when the thermostat opens, the idle goes to 3500-3750 rpm by itself and will not come down for about 90 seconds (until the engine is further warmed up). However, once the engine *fully* reaches operating temperature, it runs and idles normally. If I turn off the engine before it's fully warmed up, it will diesel (sputter-sputter) for 5-6 seconds before stopping. It will crank but not start for 10-20 minutes if I try to immediately restart it.
It's a mystery to me why it runs normally when at temperature, but has all these problems when cold and is started. Any suggestions appreciated. Ken