Advice regarding correct MAP sensor values

I have a 2011 Prius with 230,000 km on it. I am getting poor mileage and a P0171 code. I did some research and got a cheap J2534 cable and Techstream to get started, following the repair manual. My O2 sensors seem fine. I did a fuel injection volume control test for AFS, and both sensors gave appropriate readings depending on the fuel injection volume, so I think they are alright.

I read the freeze frame data, which showed the LTFT at 28% and STFT at 16% at idle. I also did the EGR valve control test, but the MAP value was at 60-70 kPa at an idle RPM of 1000 in maintenance mode. When I opened the EGR valve to step 30, the MAP value dropped a little bit instead of increasing. The engine became slightly rougher, although it was already having a rough idle but not terrible.

I am new to all this, and mechanics in my area are not very helpful in situations like this. What should I do next?

 

When the engine is not running, the MAP value is the same as the atmospheric pressure value at 97 kPa.

I have checked the MAF sensor, and it was very clean, so I didn't feel the need to clean it again.

I have been driving the car since then, and the P0171 code has not reappeared. However, the MAP value is still high for idle according to the service manual.

Driving data and idle in maintenance mode after an hour of driving with the battery half full is attached.

My concern is that I got 20 km/l (47 MPG) on a 50 km trip from work to home. My workplace is in a different city, but it's not on the highway. The roads are small with lots of curves, so I'm not driving at a steady speed, but I tried to maximize efficiency by cruising and letting my foot off the gas momentarily, then keeping it in EV range for as long as I could.

However, as soon as I am in my hometown, mostly making small trips to grocery stores and back, my average drops significantly. On the same record trip, I drove another 30 km, totaling an 80 km trip, and my average dropped to 10 km/l (23.5 MPG) from 20 km/l (47 MPG). This makes me think that at idle, it's consuming more petrol.

What should I do next?

 

I was waiting for engine to start rough idle or increase MAP value by 10 KPa but didn't happen untill i reached near 30. Only engine was rough but map dropped instead of increasing. I did and map value with battery full but is still high then 40 uper limit.

 

Yes third graph was

The P0171 code was registered at idle, with the engine RPM near 1000, but the fuel trims were high five minutes into starting the car.

I will first do a smoke test before my next long drive to check for any vacuum leaks. Then, I will record data with the long-term fuel trim as well.

Yes, the third graph was at idle. I put the car in maintenance mode to simulate idle conditions. In daily life, whenever I have to stop and wait for someone in the car or wait for takeout with the AC on, the car idles for some time, charges the battery, and then turns off.

Currently, 60% of my driving consists of long trips, about 100 km (62 miles) per day, and 40% short trips to grocery stores, each trip being about 3 to 4 km (1.9 to 2.5 miles). With this driving pattern, I only manage 530 to 590 km (329 to 366 miles) on a full tank, which takes around 34 to 38 liters, giving me an average mileage of 14 to 15 km/l (33 to 35 MPG).

I did an ABS change and an engine swap (the previous one started to burn oil at 230,000 km (143,000 miles)). The HV battery was changed 3 years ago with a lithium-ion bank, and the Dr. Prius app still says 115% health.

However, my fuel average remains the same. My local mechanic always said that this is the normal mileage for a Prius, but at the shop where my car's engine was swapped, I talked with other Prius owners who were enjoying 25 to 27 km/l (59 to 63 MPG) mileage on the highway and overall 23 to 24 km/l (54 to 56 MPG). This made me realize I should stop trusting my local mechanic and do my own investigation into why this car has low mileage.

I've been getting 15.2 km/l (35.7 MPG) average for a long time, and the 22 km/l (51.8 MPG) was an outlier due to miscalculation.