A misfire would be my guess. On a highway while on a high gear and going a steady pace try depressing the accelerator slowly so as not to cause a downshift but put the engine on a higher load. Even better if going up a small hill. The misfire usually is evident and feels like a kick under the car. If the kick is hard it may be two plugs. Consider how long it has been since last plug change and also boots. Start checking the three easy ones out front if you’re handy and compare them to the brand new replacement everyone should have siting around on a shelf.
↧