Gas Mileage Decrease and HP Loss

Fleethammer

Fleethammer

New member
2005 V8 Sport, 132K miles, bone stock, no lift, tires, etc.

I searched but can't come up with a concrete answer for my gas mileage and power loss. Since switching to winter blend gas in the northeast, I only get 19 highway and 14 max around town (used to be 12.5, but I added Techron for a few fill-ups and it boosted MPGs). There is also a significant power loss- feels like a solid 30HP- very noticeable. This differs from the summer mileage of 22 highway and 17-18 around town. That's my actual mileage computed by hand, which also corresponds to what the vehicle computer says. Yeah, I drive like a granny, but it pays off!

I have not changed my driving habits and the vehicle is so up to date with service it's not even funny. We're talking plugs, filters, ALL fluids, you name it. Tires are good, brakes are new, wheels rotate freely when jacked up- I can go on and on forever about the mechanical condition of this vehicle. I also cleaned the MAF and Throttle Body. I'm obsessive with maintenance:)

My question is- is this MPG drop and HP decrease normal for this vehicle in the winter? I always experienced this with other cars in the past, but just not this significant. This is my first truck and being FT 4WD I assume has an impact. However, my buddies who own full size pickups with V8's say they only loose @1 MPG in the winter, not 4 or so. They also claim power is unaffected.

I'm not complaining, just want to see if this is normal and if there is a frequent culprit like O2 sensors or something that may be causing the issue. I thought about just replacing the upstream O2's, but when I scan them with my Torque OBD2 app, the voltage is perfectly where it should be and AFR's are right where they should be as well.

I guess I can always wait till spring and if the MPG and power returns to normal, it was definitely winter blend.
 
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From day one, new, I have always seen 19.5 hwy and 16 city maximums
power has never changed, do not notice a winter/summer difference

Atlanta area has one of the special pollution area gasoline blends (made in Baton Rouge, La) and of course gets the RBOB volatility change 2x a year.
 
Fleethammer said:
2005 V8 Sport, 132K miles, bone stock, no lift, tires, etc.

I searched but can't come up with a concrete answer for my gas mileage and power loss. Since switching to winter blend gas in the northeast, I only get 19 highway and 14 max around town (used to be 12.5, but I added Techron for a few fill-ups and it boosted MPGs). There is also a significant power loss- feels like a solid 30HP- very noticeable. This differs from the summer mileage of 22 highway and 17-18 around town. That's actual mileage computed by hand, which also corresponds to what the vehicle computer says. Yeah, I drive like a granny, but it pays off!

I have not changed my driving habits and the vehicle is so up to date with service it's not even funny. We're talking plugs, filters, ALL fluids, you name it. Tires are good, brakes are new, wheels rotate freely when jacked up- I can go on and on forever about the mechanical condition of this vehicle. I also cleaned the MAF and Throttle Body. I'm obsessive with maintenance:)

My question is- is this MPG drop and HP decrease normal in the winter? I always experienced this with other cars in the past, but just not this significant. This is my first truck and being FT 4WD I assume has an impact. My buddies who own full size pickups with V8's only loose 1 MPG in the winter, not 4 or so. They claim power is unaffected.

I'm not complaining, just want to see if this is normal and if there is a frequent culprit like O2 sensors or something that caused the issue. I thought about just replacing the upstream O2's but when I scan them with my Torque OBD2 app, the voltage is perfectly where it should be and AFR's are right where they should be as well.

I guess I can always wait till spring and if the MPG and power returns to normal, it was definitely winter blend.
Click to expand...

And you haven't done any maintenance recently? Could be bad gas. Have you checked these basic things already? Air filter, spark plugs? Have you also tried just regular gas and not winter blend since this issue?
 
mrpanic7 said:
And you haven't done any maintenance recently? Could be bad gas. Have you checked these basic things already? Air filter, spark plugs? Have you also tried just regular gas and not winter blend since this issue?
Click to expand...

I think you misread my post. All PM has been done, including what you list. I also get my gas from Sunoco, but also Mobil, etc. basically all top tier.

In NYS, you don't have a choice of selecting a different blend at the pump, so I can't just try summer blend real quick. It switches to winter blend in the fall and then back to "summer" blend in the late spring.

Only things I can think of are fuel filter or plugged cats. O2 sensors are usually good to about 100K, but most people don't replace them until they actually throw a code.
 
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NJshadow93 said:
Did you ever try Seafoam or any other type of engine and fuel system cleaner?
Click to expand...

Yep, Seafoamed everything when I got it (TB, Gas tank, crankcase), and then just Seafoamed the TB again last week. Never saw a change with this vehicle as I have with others. It was good peace of mind though.
 
If I had to hazard a guess it would be the winter gas. I'm in the same boat as you, as soon as they changed to winter gas at the pumps my gas mileage also dropped 3-4 mpg. Sometimes worse when temperatures plummet.
 
dont get alarmed im in boston and i have an 03 runner with v8 with 37,000 miles and i go from 14.5 mpg during summer and as soon as temp goes to 50 and below i average 12.4 to as low as 11.8 thats all city driving.
 
cparise said:
my calipers were replaced 4months ago along with rotors and pads
Click to expand...

My calipers are totally free as well. Do you also have the loss of power (significant)? I feel like I'm towing a small trailer.

Based on some of these responses, the significant MPG drop and power loss in the winter months is normal. Despite this, I'm not totally convinced it's normal yet because so many other responses indicate there might be something wrong with the vehicle. I assume those folks are not be experiencing any drop in MPG or power during the winter?
 
Fleethammer said:
My calipers are totally free as well. Do you also have the loss of power (significant)? I feel like I'm towing a small trailer.

Based on some of these responses, the significant MPG drop and power loss in the winter months is normal. Despite this, I'm not totally convinced it's normal yet because so many other responses indicate there might be something wrong with the vehicle. I assume those folks are not be experiencing any drop in MPG or power during the winter?
Click to expand...

no real loss of power can be sluggish at times..all this happens during winter temperatures summertime i dont experience any of these symtoms.
 
Brazenhead said:
If I had to hazard a guess it would be the winter gas. I'm in the same boat as you, as soon as they changed to winter gas at the pumps my gas mileage also dropped 3-4 mpg. Sometimes worse when temperatures plummet.
Click to expand...

This is what I'm thinking- winter blend.

Is this your first winter with the truck?
I would suggest waiting until mid-May to give time for the winter blend gas to be out of circulation and see if your power//mpg's come back.

If they don't, then I'd look at other things- MAF sensor cleaning, maybe O2 sensor.
 
WillK said:
I notice it here in Maryland...
Click to expand...

Alright, this must totally be winter blend as suggested. Truck is running fine otherwise, so I'll just deal with it. Won't be taking long road trips in the winter so its not that important. Thanks for all the input folks :thumb3:
 
Fleethammer said:
2005 V8 Sport, 132K miles, bone stock, no lift, tires, etc.

I searched but can't come up with a concrete answer for my gas mileage and power loss. Since switching to winter blend gas in the northeast, I only get 19 highway and 14 max around town (used to be 12.5, but I added Techron for a few fill-ups and it boosted MPGs). There is also a significant power loss- feels like a solid 30HP- very noticeable. This differs from the summer mileage of 22 highway and 17-18 around town. That's my actual mileage computed by hand, which also corresponds to what the vehicle computer says. Yeah, I drive like a granny, but it pays off!

I have not changed my driving habits and the vehicle is so up to date with service it's not even funny. We're talking plugs, filters, ALL fluids, you name it. Tires are good, brakes are new, wheels rotate freely when jacked up- I can go on and on forever about the mechanical condition of this vehicle. I also cleaned the MAF and Throttle Body. I'm obsessive with maintenance:)

My question is- is this MPG drop and HP decrease normal for this vehicle in the winter? I always experienced this with other cars in the past, but just not this significant. This is my first truck and being FT 4WD I assume has an impact. However, my buddies who own full size pickups with V8's say they only loose @1 MPG in the winter, not 4 or so. They also claim power is unaffected.

I'm not complaining, just want to see if this is normal and if there is a frequent culprit like O2 sensors or something that may be causing the issue. I thought about just replacing the upstream O2's, but when I scan them with my Torque OBD2 app, the voltage is perfectly where it should be and AFR's are right where they should be as well.

I guess I can always wait till spring and if the MPG and power returns to normal, it was definitely winter blend.
Click to expand...

Winter formulation gas always results in poor mpg and loss in power.
May be more apparent in some vehicles.
 
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