Today when driving to work with thick fog, about 12 mile one way drive, twice during the drive the ICE started hesitating/shuttering. When I would take my foot off the accelerator the Prius would go into EV mode and the hesitating/shuttering would immediately stop. Did not do any of this on way home this afternoon. Anyone else experienced anything like this? My Prius is 2018 with 8400 miles, and has driven perfectly since I bought it in August.
There's a thread on here somewhere that details the stages the vehicle goes through while it's warming up. If I recall (and I've experienced this too) there is a stage where it is much more rough / shuddery compared to even when it's starting from cold. Weirdly, this stage comes towards the end of the warmup routine, so it's like the car is a bit shuddery when completely cold, then it gets better, then it gets much much worse, then it's all smooth. These stages will all be prolonged during colder weather. Could it just be that? Or is it still happening after, say, 10 minutes of driving?
Mystery solved, under the silver plastic engine cover was a mouse nest and the number 3 spark plug coil wires were bare with insulation exposed and shorting out each other causing misfire of that cylinder, engine code P0303. Removed mouse nest, isolated wires and covered with silicone heat resistant tape and cleared code. Runs fine now, at least so far.
