MPG Dropping Quickly!
- Thread starter trevo_man
- Start date
tyr0981
New member
and you'd be correct in letting the oil's get up to temp also, good oil pressure won't help if the oil is too viscus to fit into journals, like rod and main bearings, ask any REAL mechanic / "automotive technician" they'll tell you letting the engine warm up before driving is the mot commonly overlooked preventative maintenance.
Brique
New member
Ok, so I'm new to the automotive thing, so go easy on me if I'm wrong, but I would think that winter driving would actually result in better mpg once you're at operating temp. My understanding is that cold air, being denser and more expansive when rapidly heated, results in more power, and therefore lower fuel consumption.
Also, did anyone suggest the oxygen sensor as a possible culprit? A bad sensor can result in a rich fuel mixture, yes?
Also, did anyone suggest the oxygen sensor as a possible culprit? A bad sensor can result in a rich fuel mixture, yes?
BamaDrewski
New member
I have found when I disconnect my battery when working on my truck, after I reconnect it, I seem to get better mileage. Someone said it was the computer resetting and "recalculating" the fuel mix, etc. Couldn't hurt to try and see what happens.
Nunyabiz
New member
One thing I found out after taking a long almost 8000 mile cross country trip is that mileage varies depending on where you are in the country.
My straight (99%) highway MPG varied between 15 up to 21mpg and that was hauling 800# in the cargo area.
Sadly my home area is one of the sucky MPG areas, I have gotten only 12-13mpg when driving 100% city, stop and go, short trips, and about 16 to 18mpg highway the entire 2 1/2 years I have owned this truck and only one thing changed that slightly and mostly just highway MPG.
I do not have sludge, MAF is clean, Throttle body is clean, wires and plugs been changed, run 100% top quality Synthetic for ALL fluids, engine oil, gear lube and ATF are all synthetic so is not nearly as affected by cold as petroleum oil because there is no wax in it. Maintains very good flow even below 20 degrees.
I run my tire pressure right at the 44psi max and use Nitrogen so pressure changes little if any hot to cold.
I changed my 02 sensor.
Regular tire alignments.
The gas I use around town is the "Clean Power" from Costco which supposedly has a very high detergent content now to keep injectors etc clean, but I also throw in a dose of Amsoil Performance Improver about once or twice a year and Lucas fuel treatment about twice a year.
Gasoline Clean Power
I have an Ultraguage and use it to feather the gas pedal to get optimum gas mileage most of the time.
The one and only thing I have done that seems to make a small difference was changing out the Muffler from stock to a Borla and getting rid of the Intake Silencer, changed my old beat up and tiny K&N air filter for a much better AiRaid air filter that requires no oil and actually fits the box, plus already had a deckplate mod, so have better air flow both IN and OUT now.
That made little if any difference for city driving although seemed to give me I would say an extra 1 maybe 2mpg on highway though.
When I first got the truck I was getting 11.8-12.8mpg 100% city I now get 12.1 to 13.2 city.
So at best an average of about .5mpg better city.
Highway I was getting 16.1 up to 18.5 now I am getting on average "in this area" 17.4 to 19.8 (summer) so somewhere around 1-2mpg better and that was mostly if not entirely because of better air flow in and out.
My guess in your situation is simply living in a cold environment in winter and what ever winter gas Utah uses, plus probably warming the car up a bit more etc.
Its not uncommon to lose about 2% fuel efficiency for every 10 degree drop in temp so from 90 degrees to 20 is like 15% that would be roughly from 19 down to 16mpg.
You could try to reset your ECU but I would say odds are no matter what you do you wont see any better than maybe a 1mpg improvement.
My straight (99%) highway MPG varied between 15 up to 21mpg and that was hauling 800# in the cargo area.
Sadly my home area is one of the sucky MPG areas, I have gotten only 12-13mpg when driving 100% city, stop and go, short trips, and about 16 to 18mpg highway the entire 2 1/2 years I have owned this truck and only one thing changed that slightly and mostly just highway MPG.
I do not have sludge, MAF is clean, Throttle body is clean, wires and plugs been changed, run 100% top quality Synthetic for ALL fluids, engine oil, gear lube and ATF are all synthetic so is not nearly as affected by cold as petroleum oil because there is no wax in it. Maintains very good flow even below 20 degrees.
I run my tire pressure right at the 44psi max and use Nitrogen so pressure changes little if any hot to cold.
I changed my 02 sensor.
Regular tire alignments.
The gas I use around town is the "Clean Power" from Costco which supposedly has a very high detergent content now to keep injectors etc clean, but I also throw in a dose of Amsoil Performance Improver about once or twice a year and Lucas fuel treatment about twice a year.
Gasoline Clean Power
I have an Ultraguage and use it to feather the gas pedal to get optimum gas mileage most of the time.
The one and only thing I have done that seems to make a small difference was changing out the Muffler from stock to a Borla and getting rid of the Intake Silencer, changed my old beat up and tiny K&N air filter for a much better AiRaid air filter that requires no oil and actually fits the box, plus already had a deckplate mod, so have better air flow both IN and OUT now.
That made little if any difference for city driving although seemed to give me I would say an extra 1 maybe 2mpg on highway though.
When I first got the truck I was getting 11.8-12.8mpg 100% city I now get 12.1 to 13.2 city.
So at best an average of about .5mpg better city.
Highway I was getting 16.1 up to 18.5 now I am getting on average "in this area" 17.4 to 19.8 (summer) so somewhere around 1-2mpg better and that was mostly if not entirely because of better air flow in and out.
My guess in your situation is simply living in a cold environment in winter and what ever winter gas Utah uses, plus probably warming the car up a bit more etc.
Its not uncommon to lose about 2% fuel efficiency for every 10 degree drop in temp so from 90 degrees to 20 is like 15% that would be roughly from 19 down to 16mpg.
You could try to reset your ECU but I would say odds are no matter what you do you wont see any better than maybe a 1mpg improvement.
No need to be sorry, it's your money and your car. You can do as you wish.
I was a REAL Master Tech that has worked on a lot of consumer cars, and I still do work on the occasional consumer car, but far more racing engines these days.
I wouldn't classify myself as a Tribologist, but I have studied the subject at great length, so that I can make informed lubricant decisions, when a race, or just desiring a reliable consumer car engine, is on the line.
If the oil's viscosity is too high to flow through the various clearances within the engine when it's cold, then improper clearances, or the wrong oil, is being used.
Assuming proper clearances were used in engine assembly, and the correct viscosity of motor oil is being used, starting the engine and then driving easy as it warms up, is not a problem and is the most desired method from a longevity standpoint. While also being the most efficient method from a MPG standpoint.
If you start a cold engine and then just sit there idling for an extended period, the engine will be running in it's cold engine A/F enrichment phase much longer than would be necessary than if you started driving easy. Not only would you be getting zero MPG while sitting there idling, you also have a greater chance for the excess fuel getting past the rings and diluting the oil with fuel.
Fuel diluted oil does not have the same lubricating ability as undiluted oil. Which means that excess engine wear will occur. Unless you take oil samples and have them analyzed, this fuel dilution of the oil can go undetected. Then all the consumer knows is that their engine developed mechanical problems early.
All of this is known to the engineers that designed the vehicle. Which is why if you use the proper viscosity of oil, change it at appropriate recommended intervals, and follow good driving practices, such as driving gently while the various lubricants in the vehicle achieve operating temperature, you will be rewarded with a long trouble free service life.
Ain't that the truth, we keep losing all of ours around town where I am. I'm in the mountains and I can range about 15-16 unless I go to the valley where I can get about 20
