Gas mileage on my Ford Escape Hybrid has dropped to 20.1 MPG. Any suggestions on how to improve it? There are no OBD2 codes.

 

Not much info.

How many miles?
How old are the spark plugs (my first guess)?
When did this start?
Have you made any changes?
Driving habits changed?

Winter fuel is in full effect but since we odn't know your 'normal' mpg, we cant determine if this could be part of it.

 

I had about 10% (3 mpg) loss in highway gas mileage and found that changing my air filter restored the mileage.

I would also recommend using Seafoam in 1 or 2 tanks of gas to clean the injectors.

 

I will give that a try. I did replace plugs and coils (very easy to do on the hybrid) but no change.

 

As a follow up to my own advice…. My 2006 Escape Hybrid’s mileage had dropped to 27 mpg highway, so I checked the air pressure and found all 4 tires at 25#… overfilled them slightly to 38# and added 10 oz of Seafoam into ~10 gallons of unleaded 87 octane regular winter blend gasoline (10-15% ethanol). My highway mileage jumped to 32-33 mpg. No snow on the roads and outside temperatures around 32-35F.

I’m a bit surprised as this is the best mileage that I have seen from this vehicle as all summer it was around 29 mpg highway and 27 mpg city.

I had given this car the Seafoam treatment last July and at that time had seen a jump to the 29 mpg level together with the new air filter.

I’m wondering whether to attribute this to cleaning of the injectors, or perhaps cleaning of valves as the escape hybrids use an Atkinson cycle engine for which the intake valve closes after top dead center, pushing some air/fuel mixture back into the intake manifold.

I had been learning that the larger, direct injected engines would have carbon build up on intake valves which reduces their mileage due to not having the gas detergents directly flushing the valves.

prior to my has oil change, I had also added Seafoam (1 oz per quart) for ~100 miles prior to the oil change but didn’t see any improvement from that. This was just preventative as the engi only uses about a quart of oil in 5000 miles.

 

Update: I found my 2006 Escape Hybrid mileage to be fluctuating and had a P0128 error code logged along with not having much heat output for the defrost or floor heat. Present temperatures are around -10 F to 0 F so loss of interior heat was quite noticeable.

This led me to question if a stuck thermostat might cause low gas mileage… it turns out that it can.

I found a video on changing the thermostat housing on YouTube.


one of the commenters had the following to say…


From YouTube comments

And another video from Makuloco that removes the radiator fan for better accessibility.

https://youtu.be/VNcRPxGXCz8?si=Msqvnb2I1_UvBPZZ

 

KShaw, I am interested in learning what you might have found or your status.

I replaced the thermostat and find that the hybrid function now engages regularly at stopping and starting where as previously it engaged only in summer with engine fully heated. The heat for defrost and interior is now restored and working well.

I was still concerned that mileage was not 31 highway and 36 city as I was still getting around 27 for city and 29-30 for highway gas mileage.

I reviewed cleaning the throttle body and intake on YouTube and performed the removal of the throttle body and intake manifold to as far as I could reach. Then reassembled and used a can of CRC brand of spray carb cleaner to further clean the t take manifold and valves by spraying the cleaner into the throttle body intake with the engine idling at 2000 rpm as recommended on the can. (2000 rpm seems to be the normal idle speed of the engine when charging the HV battery so took no special effort on my part).

Gas mileage for city driving has improved. I am now getting 30 mpg city and 31.3 mpg highway.

I am still interested in anyone’s advice as how I might get closer to the upper limit of 36 mpg for city driving.