Really bad gas mileage and sputter at idle
 

Ok so my car seems to be getting really bad gas mileage about 215 miles on a full tank about 75% city and alittle heavy on some of the take offs i would say about 30% of them does this seem normal?. and it has a sputter on idle it never dies just sputters a little car seems to run great tho.

Edit its a 83 gsl

Also anyone ever tried Seafoam?, pouring 1/3 down the carb and 1/3 down the gas tank?

Well,
these cars are really old... The carbs are far more complicated than any other I have seen so.

1) How old is the gas?
2) Is the tank clean and free of rust (that might be getting into carb
3) When was the carb last rebuilt?
4) Is your butterfly valve (below carb - shutter valve) stuck closed? Do you have full power as far as you know?

Scott

How to calulate your MPG:

1. Fill up car.
2. Reset trip odometer to zero
3. Drive
4. Fill up tank again, noting how many gallons go in.
5. Get mileage info from trip odometer, and divide that number by the gallons that went in.


Expected MPG:

1. Car in perfect condition, driven by little old lady = 24 mpg
2. Car in serious need of tuneup, driven by little old lady = 16 mpg
3. Car in perfect condition, driven by young teen who thinks he's the Stig = 16 mpg
4. Car in serious need of tuneup, driven by young teen who thinks he's the Stig = 8 mpg

Advice: Start by making sure ignition system is functioning. Pull all spark plugs and confirm spark.

Seafoam: I love the stuff. Car responds great to it, always feeling additional pepp. Dump it in the tank, don't try to get fancy by pouring down carb or sucking through vacuum line.



.

i did a full bottle of seafoam into the vacuum line and my milage went up and the car feels much more peppy

I have a 91 NA and my car sputters sometimes at the stopped position. Could it be my shutter valve. If so? around how much would it cost to get it repaired?

Try driving the speed limit :P Saves a LOT of gas because of how these cars are geared.

55 MPH in 5th gear = 2500 RPM

The amount of fuel consumed rises greatly as the RPM's do.

The high RPMs where all the fun is!

Fact.