My wife tells me she's only getting about 13mpg.
I've changed the plugs, coil, plug wires, and performed all basic maintenance items.
Any idea what could be causing the poor mpg?
She does drive ONLY in stop and go traffic 99% of the time.
I realize that she should be getting lower mpg than normal but this sounds ridiculous!
My 5.5l AMG V8 motors get similar gas mileage in stop and go driving also!

 

how is her right foot? also did you do a tranny flush and o2 sensors?

 

BPV? I have heard of people wire tiring theirs open and getting horrible MPG but increase of bottom end performance. It's "possible" that the BPV might be stuck open?

 

I think she drives "reasonably" LOL!

I did the tranny flush but not the O2 sensor. I was thinking that also.

 

Sorry for my ignorance but what the heck is a "BPV"?

 

Wonder if she has a dragging brake caliper....fairly common on the rears....
Drive around the block....try not to use the brakes...then see if one is hotter...
The fact she drives in "stop and go only" means unless she is pretty laidback, mpg is gonna be pretty crappy....

 

Never thought about that! I'll check.

Here in Honolulu traffic in town is really bad during rush hour.
She drives only about 4-5 miles max but it's in the worst traffic.
But damn! 13-14mpg??? From a four cylinder???

By the way, can you point me to any rear brake discussion?
Wondering how you fix a dragging caliper?

 

superchargers are very thirsty in nature, going around my town ill get about 15 mpg, im also using boost, which is thirsty as well.

brake caliper drag is also another good idea to look at, just take a drive around the block, dont use any brakes, then if you can reach under the car and see if one of the calipers are warm and radiating heat, check the fronts as well for comparison. another way to check is if the pads are wearing differently side to side in the caliper and side to side on the rear.

to fix a dragging caliper, it needs to be rebuilt or replaced, same with the pads and the rotor

you could also take it for a normal drive not in traffic and see what kind of figures you get. traffic uses quite a bit of fuel

 

The rear calipers typically fail internally... And don't retract...a new/rebuilt unit is the solution...but a bad handbrake/ebrake cable can do the same thing...
Trick us to see if the handle/cable is moving and releasing freely...if so, the caliper is bad...if you have one dragging.