Recent drop in MPG (17 MPG to 13 MPG).

[Fastcar]

I had all 4 tyres replaced about 6 months ago and they did a balance as part of the tyre change. Have used this garage for 6+ years and they let me watch. They have always been very competent and I trust them completely for anything to do with wheels and tyres. The car has no shaking at any speed on the road.

Sorry, I screwed up and replied to the wrong item.

 

[Herby]

I recent had the same concern with a severe drop in gas mileage from my 2007 Expy. On the highway, I would reach 17 to 18 mpg. On a recent trip road trip, I was averaging 14 to 15 mpg. The problem was my fuel injectors. Once I replaced them, gas consumption went back up to my norm of 17 to 18 mpg. I purchased Motorcraft units. I figured since my originals lasted for almost 250k miles, I would go with the same proven parts. Good Luck!!

 

[Gary Waugh]

Herby, thanks for the input, but why would bad fuel injectors increase fuel consumption? Surely they would just inject less fuel causing a lean condition, possibly damaging the engine but not increasing fuel consumption? I have always added fuel injector cleaner to every second fill up, so I hope the injectors are in good shape, but it sounds like I need to take a look at them.

Regards Gary

 

[czer]

So did you notice decrease in mpg before or after you bought new tires? If after, a change in tires can change mpg.

 

[Gary Waugh]

The drop occurred before the new tyres. Still messing about trying to decide whether to replace the O2 sensors or the fuel injectors!!

 

[durb]

tire size 145 155 and 165 will all fit. but will affect the speedometer and fuel milage

 

[Gary Waugh]

The new tyres were the exact same size as the old tyres, just not worn out!! I noticed the drop in MPG before the new tyres were fitted, so I still think the car is probably running richer than before, so just want to try and find out why.