This time of year, if you are in one of the PC states you will be getting rotten gas mileage. Also, the tank may contain one to three different blends in any given area. Locally we went to 'winter gas' and everyone’s mileage dropped 2 mpg, just like every year. This uses more gas and raises the costs a lot.

You may stop by one station and get leftover summer blend and suddenly get much better mileage. Or the reverse is true.

Within 30 mile of my house there are 4 different blends sold in January.
Bad, worse, terrible, really rotten.
In summer there are three blends. Not so bad, lousy, pretty bad.
(Sorry to get technical)

Anyway, you can not make a real call on one tank or two, unless you compare the same blends.
This makes it very hard to judge tuners, mods, this time of year.
Chris

 

Maybe where you live. Not everywhere. I would be carefull not to make blanket statments like that.

 

I got my best mpg reading of 18 on my last tankful of Shell 87. Just recently switched and have noticed a small increase in fuel economy over exxon. Here in TX we seem to get better gas.

 

sorry, I'm just quoting what I saw on the History Channel, I fugure that they have a pretty good idea of what they're talking about. It was an executive from BP I believe that was talking about it. He said that there was no way of telling what brand of gas was going to what stations, only octane levels

 

I had always used independents, usually a few cents cheaper, Kroger, Race Track mainly. Then I tried Exxon and according to my records I do get a little better mileage with the Exxon. I would never have believed it had I not kept records for the last 15,000 miles. I had always believed it all came from the same pipeline, so was the same gas. I will have to try Shell. Who owns Shell now?

 

Last I heard Texaco and Shell merged. Not sure if someone else own's them now.

 

I noticed using the Wal-mart gas my truck smelled like rotten eggs when I parked and got out.

Now I'm using Citgo and have zero smell problems and I've seen about a 1mpg increase. The Edge hasn't really helped my mileage any that I can tell.

 

Yes, it was Texaco, thanks.

 

All the Texaco's down here in SA turned into Shell. Texaco/Shell are consistantly 4-5 cents higher than Exxon, Chevron and Vallero; any reason for this?

 

I know shell uses many more additives than others. Maybe that is why. Up here in Michigan they are competitive with other stations. Maybe the change in fuel comes at the individual station. Many "bargain" fuel places are always packed so I know the gas is not sitting in the tanks. Yet I get 1-2 mpg less when I try them. I think they are cutting it with ethanol or something.

rltripp
I guess I am not at the pipeline when it is going in but I have 3months and 9k miles of data with each station listed, driving conditions, date, etc... for this truck. I always get 1mpg better with shell. I can't explain it but numbers do not lie. Maybe I was just lucky.
__________________

 

Considering the shell, exxon, valero, and receway stations can all see each other's price signs in my hometown they all have the same prices. Competition is good.

 

I'm getting my truck lifted next friday.. procomp 6inches with 35" mud grapplers... What kind of mileage can I expect then? 11-12? i drive a mix of city and highway

 

From what I've learned, most gas (and diesel) goes through the same pipeline. I think there are some additives that certain companies add prior to distribution. The cheaper stations get the gas that goes through the pipeline first (after the diesel) so that's probably the source for the rotten egg smell that some have noted. The more "premium" gas that goes to the "name brand" stations is the last stuff that goes through.

I could be completely off tho...

 

Nope, not that I've noticed. I'm still averaging 17-18 mpg no matter what brand in town I've used.

 

I really don't care what my mpg is...right now its close to 15...I didn't buy the truck for gas mileage!