gas mileage & throttle response

by **Masshole** » Thu Oct 21, 2004 7:47 am

As the weather is getting colder I've noticed my gas mileage has taken a dive(350/tank with 70% highway on 87) and my power in general seems to be down (seat of the pants feeling) especially on 87. I do not have any check engine lights - this is a 99 auto 3.0 with 102k miles - plugs & wires (denso ik22 ngk blues) fuel filter, K&N all new with regular oil changes. Are there any sensors that might be malfunctioning enough to throw things off but not cause a CEL? I especially think the cold weather is having an effect so perhaps there's an air charge sensor or something that could be out of whack?

Any suggestions are greatly appreciated.

by **bassthrive** » Thu Oct 21, 2004 8:18 am

Your engine should make more power with the colder air. Maybe your stations already made the switch to winter gas? I dunno....

by **Masshole** » Thu Oct 21, 2004 8:22 am

I know cold air is denser and should make more power which is why I'm baffled.... never heard about "winter gas".

by **bassthrive** » Thu Oct 21, 2004 8:28 am

Hey this may seem like a "duhhh-yeah" suggestion but check your tire pressure. The cold weather may cause your tires to be a few psi low, which will effect your gas mileage and performance.
:drinking:

by **SC V6** » Thu Oct 21, 2004 10:39 am

ecu could also be adjusting

by **Mole** » Thu Oct 21, 2004 12:06 pm

possible injectors are clogged.

it might just be your head.

by **Masshole** » Thu Oct 21, 2004 12:08 pm

I'll check the tire pressure. ECU adjusting for waht? a colder temperature? I would think that would be automatic pretty much.

Injectors clogged... wouldn't that throw a code?

You're right it could be my head - but I filled up with 87 and did normal driving (70% highway I'd say) and got ~350 miles on the tank - that's just barely over 20 which seems pretty crappy to me... don't you think?

by **Mandarinsolara** » Thu Oct 21, 2004 5:35 pm

is altitude a factor? dads old mustang loved the air in californias mountains 10 times more than here in jacksonville

by **Fletch** » Fri Oct 22, 2004 5:47 am

Around my area, they switched to winter gas at the beginning of December. I don't think it will make a difference in performance/economy though.

by **DatSRBoi** » Fri Oct 22, 2004 7:27 am

Maybe the car is getting old? Or maybe your driving style changed.

by **Masshole** » Fri Oct 22, 2004 8:20 am

Altitude is not a factor and my driving style has not changed.

Yes, the car is getting old which is why I was wondering if there are any sensors that may need to be replaced that are not throwing a code. On that line of thinking, are valve adjustments ever necessary on these cars when they get up there in mileage? I have changed the oil religiously so the internals should be fine.

by **SE4ME** » Sat Oct 23, 2004 7:57 am

Could be a number of factors - such as not getting the tank as topped off as you think.....

Brake calipers dragging??

Quality of fuel.....

gas mileage & throttle response

gas mileage & throttle response

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