more info on my terrible gas mileage

[Pontiac Racer]

i posted a thread a while back about how i get terrible mpg and about 210 miles until i have to fill up again. well i learned that my mpg drops during an idle. i can reset the trip computer and it'll read like 20mpg ya know normal, then after i get a stoplight it'll drop slowly down to about 13mpg and then sit there and slowly fluctuate to like 13.6 while driving. so it drops a lot during an idle. it idles fine. I'm thinking ill clean the mad and TB when its warm out. do you think that'll solve the issue or is it something more? hammy

[Pontiac Racer]

maf, sorry. autocorrect

[Slick2500]

I don't remember your old thread. Is your MIL on? Do you have a scan tool of any kind to check your fuel trims?

[Scottydoggs]

if you reset the dic then drive 4 blocks or a mile or two, yeah its gonna drop like a rock when at idle.

if you drive the highway for a good distance daily it will stay higher while driving local.

if all you do is drive local, welcome to crappy local mpg. im at 14 to 16 if i baby the crap out of it. all i do is local.

but on the highway, ill do mid 20's to 30 easy.

[Pontiac Racer]

Whats MIL. Yes all i do is drive city. But it still doesnt explain why i get 210 miles per tank. But why does it drop at idle. If anything shouldnt it rise because the engine is sitting at 700rpm and doing zero work. Doesnt make sense to me

[Scottydoggs]

mil is the check engine light.

these cars drink gas at idle. dont idle. get to where you are going, shut it off. dont fire it up till your ready to leave. how i roll.

city driving mpg full time flat out suck. if your like me its all stop and go, 35 mph top speed for a mile tops, then a light or a stop sign, its all the stop and go that kills it.

[stealthee]

Whats MIL. Yes all i do is drive city. But it still doesnt explain why i get 210 miles per tank. But why does it drop at idle. If anything shouldnt it rise because the engine is sitting at 700rpm and doing zero work. Doesnt make sense to me

Please explain how MILES per gallon will increase when no mileage is being added? You are burning fuel and not moving therefor MILES per gallon will drop. You are getting ZERO MILES per gallon at idle.

[Fivefingerdeathpunch]

220-250 was great for me in the summer, thats like 16 mpg or so.

And I drove it 5 miles per day to work and back.

[99GT2dr]

Lol, what stealthee said bro. Taking it to the other extreme, going down a hill throw it in neutral and watch your mpg skyrocket. Engine is doing near 0 work and still traveling xx mph.

[HighOctaneRacing]

Since I'm on tapatalk, I can't see you location but are you located in a cold place? Cold weather will take some air out of your tires over time so check the pressure. Winter blend fuel sucks ass too. Tune up may help along with a fuel filter if you have one. Just some ideas.

[Pontiac Racer]

Im in WI which as you can guess pretty cold. I did make sure to check my tires and they're all at about 31psi. One may be at 30.5. Would cleaning the maf and TB help? And a new air filter? The car has never had a tune up so everything is original. Obviously not the common stuff like brakes, oil, air filter, etc. but im not sure when the filter was changed. Any good ones i should get?

[Scottydoggs]

only one things going to help your local mpg. and thats to not drive local lol

its how it is if its all you drive.

this is one of my better days.



one of my more normal looking days. ill hit 12 and lower if im beating the crap out of it .

[stealthee]

I'll add to this with my own experiences of right now. Before I changed jobs I was driving 17 miles to work. Of that 13 miles was highway/bypass and I generally got 23 mpg in the summer and 19 mpg in the winter. The biggest factor in winter mileage was letting the car warm up before I left.

Now I have a job that is 4 miles from my house. Summer mileage is lucky to hit 19 mpg and is usually closer to 17 or 18. Winter mileage is now around 14 mpg.

The combonation of idling, colder denser air burning more fuel (especially while idling), and crappy winter blend fuel which doesn't aid in fuel mileage either, will destroy ones MPG's in a heartbeat.

[HighOctaneRacing]

Im in WI which as you can guess pretty cold. I did make sure to check my tires and they're all at about 31psi. One may be at 30.5. Would cleaning the maf and TB help? And a new air filter? The car has never had a tune up so everything is original. Obviously not the common stuff like brakes, oil, air filter, etc. but im not sure when the filter was changed. Any good ones i should get?

Well what's the mileage? If you have close or over 100k, a tune up would be a good idea and cleaning the TB is never a bad idea provided you do it correctly. Clean the MAF with MAF cleaner only. As for the air filter, it's your choice. I use NAPA Gold which WIX makes NAPA's filters and WIX is great.

[BillBoost37]

Your name is Hammy?

Hammy.... there is no miles per gallon when you sit still. This is because when you sit still.. you aren't moving. Miles per gallon would insinuate that you were moving along miles.

City driving can really kill off mpg's. Look at Scotty aka Jersey (sit in traffic) Doggs. He gets 15mpg on a good day. I get 24-25 mpg because I put on 40 miles and half of that is highway. The rest is moving along on backroads