Motor knocking

When I start my 2012 prius the noise scared me. The motor shook an inch and a half first tow found nothing. It did it again drove it in nothing found could not duplicate. Third time towed and again nothing found. "It is safe to drive we can find nothing wrong". After asking for a manager and inquiring about lemon status I was given a car to drive. The service rep said a manifold would be in in about a month but the mechanic supervisor said there is no eta and we are working on it.
A week later they call the manifold was replaced and they finally duplicated the issue in one of the other three cars there with same complaint. I was getting 50 mpg until this started when I took it in I was getting 46mpg. Now after the first 300 miles since I got it back I'm getting 43.5mpg. Is anyone else dealing with this issue with results
Frustrated

 

alabama
- Have you read This Thead Yet?

- What fuel economy are you getting and how are you determining fuel economy? (trip computer or manual calculations)
Trip meter and monthly avg use

- What fuel economy are you expecting and why? 50 mpg because that's what I avg the first 3 months I had my car. I drive 60 miles one way to work 5 dad a week

- What are the approximate outside air temps? Range from 70 to 28 now

- How long are your trips? Hour and ten minutes

How old is your 12v battery? What is the voltage reading of your 12v battery after sitting over night? (Method Here)
No clue
Have you had your alignment checked? Any pulling or abnormal tire wear?
Services done as scheduled by Toyota
- How much of it is city vs. highway? Roughly what's the average speed in overall and and of each segment? Is there a lot of stop and go driving?
Highway mostly cruise control on 62 mph to work. Avg according to car around 48mph
- What's the terrain like of your drives? (e.g. flat, gentle hills, steep hills, etc.)
Gentle hills and flat
- What are your tire pressures? I don't know

- Is your oil overfilled? (i.e. above the full mark on the dipstick) I assume Toyota would not overfill

- Make, model, year, engine and transmission of previous car? (e.g. 08 Honda Civic Si 2.0L 4 cylinder, manual transmission) What did you actually get on the same trips/commute? (Please give us actual numbers, not EPA ratings.). Honda crv 2007 appr 30 mpg

- What region/state are you in? (if you haven't set your location) alabama

- How are you trying to drive (e.g. trying to stay in electric only?) and how hard are you braking?
Cruise
- What modes are you using, if any? "normal", EV, power, eco?
Eco
- Are you "warming up" the ICE (internal combustion engine) by letting it idle after powering on? Till ready on

- Are you driving using D or B mode? D

- HVAC settings? Are you using the heater, AC, auto mode, etc.? If using auto, what temp is it set to? Heat

- Are you using the factory tires and wheels? If not, please indicate tire make, model and size (e.g. Goodyear Assurance Fuel Max 185/65R15). Yes

- If reporting a mileage drop, did anything significant change on your car (e.g. accident, hit a curb or big pothole throwing off alignment, oil change/other maintenance/repairs, changed tires or wheels, etc.) or your commute? No

Read more: Fuel economy complaints/queries? Please copy, paste & answer these questions, esp. if you're new | PriusChat