A month or so ago I had the car in for service and caught up on a couple of major service items that I skipped while I was job hunting. I got my 04 HCH MT software updated, all required maintainance for my mileage (~130K) including tuneup and new plugs, new tires, alignment, pretty extensive transmission service.

Prior to the service I was getting high 40's for both gage and calculated MPG, every since tank, with the B odometer running nonstop indicating 46-47MPG lifetime.

Now I am LUCKY to get high 30's both gage and calculated, hitting 40 for exactly one tank since the service. I will admit that the gage is much closer to the calculated figure than prior to the update, but surely something is very wrong here. My local dealer carried out all the service items and I got every single thing they indicated was suggested and/or required.

I did notice that when I got the car the gage MPG and battery charge state were not reset as I expected.

I have NEVER gotten this low fuel economy since the day I started driving this car and now other than riding HOV I am really having all the disadvantages of a hybrid with none of the advantages.

Any tips, things to talk to the dealer about, things I can do on my own? It pains me to hop in ot the gas station under 500 miles per tank when I was getting ~600 every tank for 3 years!

 

Filled up today with the gage reading 36.3 and calculated MPG at 37.22. I've never had a series of tanks this low, even with AC on and crawling in traffic.

 

What type of tire did you replace. I had kumo kr 21 installed on my 07 and have seen a 1.5 mpg less over 4k miles. However the ride and handling improved over the Bridgestone so much I can live with the reduction.

Brian

 

I'd guess your tires, had a new set effect economy on my Tribute by 3-4 MPG

 

No way tires are going to cost you 8-10 mpg, even if underinflated. Something else is wrong. Take it back in, explain the extreme drop in MPG and ask that they double check all fuel/air related items (ECU, O2 sensor, EGR valve, etc.). When something changes that dramatically immediately following a service, you can be pretty darn certain it was related to the service.