: Where did my MPG's all go????



1990CaddyBrougham
01-28-07, 09:58 PM
I dont know whats going on here! I use to bank alot more miles on a tank.

Im down a bar below the 1/4 mark and have only traveld 215 miles. Id usually be ataleast 100 more

I did plugs, wires, cap ect a while ago, less then a year.

I did put studed snow tires on the rear, but i wouldnt think they would take away that much...

Anything else i could be missing?

I cant drive like this, at this rate i would have to cash in.

Anthony

90Brougham350
01-28-07, 10:04 PM
The tires shouldn't cause that much of a decrease, unless they're severely under-inflated. Have you been doing a lot of city driving?

The Ape Man
01-29-07, 05:02 PM
Dunno if you have winter blend fuel but if you do it sucks.

Old Fleetwood
01-29-07, 10:20 PM
Adding to the above:
>Winter fuel (as noted above - good for lousy mileage. Feds mandate in certain areas :crying: )
>More idling for warmup (a sure mileage killer - I'm doing it :o )
>Snow Tires (Possible change in diameter affecting odometer reading? Inflation affecting drag - that can be worth a mile or 2)

bigbluebrougham
01-30-07, 02:33 PM
I dont know whats going on here! I use to bank alot more miles on a tank.

Im down a bar below the 1/4 mark and have only traveld 215 miles. Id usually be ataleast 100 more

I did plugs, wires, cap ect a while ago, less then a year.

I did put studed snow tires on the rear, but i wouldnt think they would take away that much...

Anything else i could be missing?

I cant drive like this, at this rate i would have to cash in.

Anthony

This is just a shot in the dark. It happened to my 1993 Chevy K1500. My float went bad at 130k, but I noticed that I was putting in less fuel in at the pump. Dropped the tank to change the float and pump and it fixed itself. I notice you didn;t say whether or not you were putting in more or less gas every time. I live in SD and I know my car gets bad mileage inthe winter, but not THAT bad. I usually lose anywhere from 25-50 miles per tank. It all depends on the weather and temperature. Today it was a balmy -10 this morning and I know I let my car warm up quite a bit...

N0DIH
02-01-07, 08:04 PM
Mine has been down lately, but it has neen very windy lately. And in my tuning, I messed with the timing and upped it some, and what I have found is LT1's aren't too fond of part throttle cruise. So I looked back at my mpg log and went back to the timing map that I had then and mpg has seen to come back up right away.

The more efficient the head, the less the timing requirement for most efficient operation. So be cautious with messing with too much timing, more isn't always better.