I am experiencing a sudden drop in gas mileage. Normally I get about 300-320 miles before the indicator light comes on. This is under normal everyday driving commuting to work and running errands. On longer trips I usually get 400-420 miles. Lately I am only getting 270-275 miles. My driving has not changed, I still go to all the same places under the same conditions.

Two things have changed on my car around the time of the mileage drop. My transmission died and was replaced and I put new tires on the car. Would either of these have this affect? I wouldn't think the tires would have that drastic an impact, went from Yokohama to Bridgestone.

Is there anything that can be adjusted/inspected that would get me back to where I was? If it matters there are 63000 miles on the car and I only use 93 octane gas.

Thanks for the help.

Ken

 

Sounds like the transmission might be slipping a bit. I would check the transmission fluid level and make sure it is full. Also, the torque converter lockup might not be locking up - I don't know how to check that for sure. Or nothing could be wrong and the ECU is just learning the new tranny and your driving style.

 

Different tires will vary in gas mileage. High performance tires, touring tires, etc.

 

Thanks for the suggestions, I will check the tranny fluid level. If it seems OK I guess I will wait until I have it in for its next service and have the dealer check it out.

I went from the Yoko Avid V4S's to the Bridgestone Turanza LS-V. I wouldn't think it would have that much of a difference.

 

change air filter/o2 sensors?

 

Doesn't hotter + more humid air hurt mileage? I know its been hot as hell here in MD for the past few weeks. Im sure your running the A/C more often now also.

 

Its the summer, you are probably driving with your A/C on more.

 

Forget about 'miles per tank', which is meaningless. What has your miles per gallon changed to?

 

I experience the same up and down in MPG from tank to tank....How many times since the new tranny installation have you filled up and checked the mileage?
The new tires are a likely cause...try increasing the pressure to 36 front/34 rear.
Thats where I keep mine and check them once a week.
I find when I'm waiting for the wife outside a store with the engine/a-c running for 20 or 30 minutes, that tank of gas mileage will be crap. Driving style and things like that will also impact my MPG greatly in addition to the warm weather as mentioned by Zero and others. Air filter, check it as well.

 

No. If any of the above were happening you'd get a check engine light - or more likely the "Acura Christmas Tree" lighting on the dash.

I think it's tires as well. Check your tire pressure - and make sure your air filter is relatively clean as well.

 

when i first opened up my air filter, pure leaves....like almost to the point it woulda been cloggin it.

 

tires can and will make a difference. Also we are all running 10% ethanol now in fuels which you will most likely see a drop from that as well

 

When the indicator light comes on I consistently put 14-14.5 gallons inthe tank. When I was getting 300-320 miles per tank my mileage stayd pretty consistent as well at 21-23 miles per gallon. Now when the light comes on I have 275 miles on the odemeter and still put in 14-14.5 gallons, dropping my mileage to around 19.

I fill the tank every week. Tranny was replaced in April. So I have fillled the tank 7-8 times since then.

I keep the tires at 32psi all around and check that pretty regularly. The K&N is due for a cleaning so I will check that and see what happens.

 

Just curious, where in MD are you?

 

I currently live in Ellicott City, but I am building a house in Elkridge.

Generally, I live near where routes 95, 175, 100 and 108 come together.

 

When I changed from the original Michelins that were worn down to the tread bar indicator to Yoko-Avids my mileage when down about 3 miles per gallen.