I am having issues with a 2006 Gen II Prius that just approached 120K miles. When going down a hill at approx. 35-40mph, the engine jerks when downshifting or when coasting. At 35-40mph on flat ground I will be coasting, and then press the petal softly (to try to pulse and glide) and the engine/car jerks when re-engaging the ICE. This can also happen at low speeds of 10-15mph on flat ground when the engine "hiccups" and then shifts instead of smooth transitions. This Prius has always had regular maintenance and oil changes, but I am wondering whether this is the spark plugs? or something in the engine more serious? Thanks folks.
Not possible, since the Prius does not have shiftable gears and lacks any clutch for disengaging the engine. There can be a noticeable shudder when the ICE powers up, which is likely what you are describing. Is this a new situation for this car? Tom
Exactly. The shudder is more pronounced in the last 3-5K miles and always occurs at specific speeds of about 35-40mph. It could be my bad memory, but the car was a lot smoother in its early days.
Most benign possibility: dirty throttle body. Most malignant possibility: Trans is on its way out. Try cleaning the throttle body first. Next would be a drain and fill of the transaxle fluid. Catch a sample and send it for analysis. Search here for details on that process. It would help if an experienced technician could test drive the car.
