Does Fuel Injector cleaners cause worse MPG during initial fill?

[Jackphom]

Currently own a MK7 GTI with direct injection, bought the car pre-owned at 34k miles and it seems like the prior leaseholder took it in for every scheduled visit. I've only ran fuel injection cleaner through a tank twice now and I'm at 56k miles. Just recently filled up with some Gumout Regane, I don't know if it's the winter gas blend or the regane causing some worse than normal mileage.

I'm just curious if anyone else experiences the same when using an injector cleaner.

 

[B1974]

Probably the winter gas blend. I've never noticed any difference in mileage due to injection cleaners.

 

[UG_Passat]

are you tracking the tank mpg using an app like Fuelly? Or are use manually tracking using excel spreadsheet?

Because you're really not providing any detail to your "observation"

 

[Jackphom]

are you tracking the tank mpg using an app like Fuelly? Or are use manually tracking using excel spreadsheet?

Because you're really not providing any detail to your "observation"

I admit, I'm being lazy and I'm using the MPG readout on the car. But I'm due for a fill up soon, I'll hand calculate and see if there is any major difference

 

[Speedy3861]

I hand calculate every tank as well as follow the dash indicator, have noticed my CRV mileage has dropped about 10% with the winter gas we seem to be getting, using mostly Shell 87, sometimes Exxon 87. It's also generally colder too, nighttime temps in the mid/upper 20's, I'm sure that's having an effect. Since I use Toptier exclusively, haven't used any cleaning additives, back pre 2015, with my previous Honda Civics, I used a bottle of Techron before each oil change at 5k, never noticed any drop in mpg.

 

[Jackphom]

I live in Jersey City now, so it's all stop and go. Rarely go on the highway for anything, so I measure it by my tank to empty, usually I'll grab like 220 to the tank driving around in the city.

 

[Graham Piccinini]

It's probably related to winter blend. Also, since it is slightly colder, do you let your car warm-up a little longer now than you did in the warmer months? If so, then that would account for some of the MPG. And lastly - if I "overdose" (double or triple the recommended dosage) my fuel with Lucas UCL or Marvel Mystery oil, then I do see an MPG drop. Experienced that trend on at least 5 vehicles so far. All MPG hand calculated at pump.