MarcusMIA

I have a 1996 SC400 with 131K miles on it and I had a tune up about a month ago or so and I was getting over 300 miles a tank. Now I'm getting just like 130 miles with half the tank gone...

I remember filling the tank up and I got like 250 miles or less maybe... What the hell could have caused this? Before I was getting like 360 with the needle almost touching the end

All I have done throughout the course of these last weeks has been:

1. Add almost an entire can of seafoam to the tank.
2. Refilled the transmission twice. (4 quarts)
3. Oil Change. (Mobil Clean 5000 for now)
4. I added some Restore to the oil. (Cures micro scratches on cylinder walls, for those that don't know of what I'm talking about).

I do notice that the car is moving more slick and pulling harder, but damn... It can't be that much... I drive mostly highway, too...

It seems that with the same throttle pressure as before the car is shifting at higher RPMs... REGARDLESS... I don't speed that much.

EDIT: Is it the fact that it's like 40 degrees in Miami!??! ****!

Ali SC3

iTrader: (10)

longer cold start = more fuel. definately contributes but 100 miles is a large difference

jadu

iTrader: (42)

Winter gas = less mpg

jadu

iTrader: (42)

And, how long was it between seafoaming your car and changing your oil?

TheMole

iTrader: (13)

I'm not too knowledgeable about seafoaming, but I remember reading something about changing the spark plugs afterwards.

MarcusMIA

I heard you should change the spark plugs if you put the seafoam through a vacuum hose. I put it in the gas tank. When I did it through a vacuum hose I got a tune up right away.

Why is it that winter gas = bad mpg?

704sc300

iTrader: (1)

I also have BAD MPG for the past two months now... My friend's Hemi truck got better mileage then i do lol....