need suggestion about mpg

39 isn't much below average. stop and go traffic takes a tremendous amount of energy to repeatedly get the car moving from a standstill.
best to measure your mpg's at the pump and calculate average over many tanks.
what types and pressures? clean air filter? hvac use? 12 volt and hybrid battery condition?

 

Ensure you're all updated on maintenance and try the pulse-and-glide method. I can get 65 mpg in both our Prius and my wife's Corolla Hybrid. Ahmed (The Care Care Nut) explains it in this video:

 

might need to clean the egg circuit as well

 

It seems like you are not getting enough speed to produce good regen. It seems like most of the engine power is going to move the car so u are burning more gas and not enough to charge the HV battery high enough to get better mpg.

Try to get the battery bars to full. Like driving it on the highway (motorway) for a while until bars are at full. Or drive it somewhere at stop and go speeds above 25 mph. Your trip data is showing 6mph and a distance of 12 miles. Which means you drove at a joggers pace for 2 hours? You could also be sitting in traffic a lot or parked while the car was on ready mode for quite some time which would drain the HV battery fast. The car used it all it's EV charge and then went only on gas. Not enough to charge the HV battery to full. But still you got 39 mpg which is still good for your driving situation.

 

Also in my opinion, this type of driving will not be good for your catalytic converter, your egr valve, and your engine may wear faster. Higher speed is like exercise. It will help clean out the arteries valves and circulate the engine oil better. The catalytic converter needs to do it's work at high temperatures so low speed will not help it. Slow speeds can clog it more. And more carbon build up can lead to more clogging of the piston rings and engine in general. I recommend Sea Foam in your gasoline at least once or twice a year if driving at low speeds is normal.

 

It's states that it "prevents build-up of deposits" so that should help. But once in a while driving at high speeds is good for your car and the catalytic converter. Hybrids that tend to last the longest tend to drive lots of highway miles.

AI response to highway vs city driving for hybrids:

"Hybrids that drive mostly highway miles generally last longer and experience less wear and tear compared to those driving exclusively in stop-and-go city traffic. While city driving maximizes fuel efficiency via regenerative braking, highway driving allows the gasoline engine to maintain consistent operating temperatures with less friction and less frequent cycling of the high-voltage battery.

Engine Longevity: Long-distance highway driving reduces engine wear by allowing it to reach optimal operating temperatures, preventing the sludge buildup often found in short-trip, city-driven vehicles.

Battery Stress: City driving uses the electric motor and battery constantly for acceleration and regenerative braking. Highway driving relies more on the gas engine, reducing the constant heavy cycling of the battery pack.

Component Wear: The frequent stopping and starting in city driving places more stress on the transmission and hybrid system components compared to the steady-state, lower-RPM cruising of highway driving.

Efficiency Nuance: While highway driving increases longevity, it is important to note that many hybrids are designed to be more fuel-efficient in the city, where they can hit 50+ mpg, whereas highway speeds (over 70 mph) can reduce that efficiency to the high 30s or low 40s mpg"

 

I've been driving my 2011 for years in city commute, 36-37 is the ave mpg. Hardly any highway driving and it's been chugging along. Still waiting for the hybrid battery throw its' death code. I gave up long ago on trying to get the mpg up.

 

Older Toyota nimh packs do not have the longevity and durability that newer Toyota nimh packs have.

AI summary of this:

"Toyota made significant improvements to their Nickel-Metal Hydride (NiMH) battery technology around 2015, focusing on reducing self-discharge, increasing energy density, and improving overall longevity.
If owners of older Prius models replace their packs with a new, current-generation Toyota NiMH pack, they will receive these modern improvements, as all new Genuine Toyota replacement packs feature the latest advancements.
Improvements to Toyota NiMH Batteries (Post-2015)

Reduced Self-Discharge: Modern Toyota NiMH cells can hold up to 85% of their charge after a year, a significant improvement over early-generation Prius batteries.
Improved Energy Density: Improvements in materials have allowed for higher energy capacity within the same volume, allowing the batteries to handle the demands of hybrid driving more consistently.
Better Reliability: Enhanced manufacturing techniques have helped eliminate impurities that cause cell failure.
New "Bipolar" NiMH Technology: While earlier NiMH improvements were incremental, Toyota has now begun rolling out "bipolar" NiMH batteries in some models, which offer twice the output power and faster charging/discharging.

Benefits for Older Prius Owners
If you replace a failing, older NiMH pack with a new, genuine Toyota pack, you gain:

Enhanced Performance: A brand-new pack will show significantly lower internal resistance compared to an aged one, resulting in better acceleration and less engine stress.
Improved Fuel Efficiency: Modern cells and better balancing allow for increased energy efficiency and better MPG, restoring or sometimes slightly exceeding original, aged performance.
Lasting Durability: New Toyota packs are designed to last for a long time, often outlasting the vehicle itself under proper conditions.

Note: While new Toyota NiMH packs are better than the old ones, for some older models, aftermarket Lithium-ion options (like Project Lithium) are increasingly popular for lighter weight and higher efficiency, though a new Toyota NiMH pack remains the safest, most reliable drop-in replacement."