Poor gas mileage??

[CaliCuttie]

Hey G-Body people,
So my gas mileage has been a concern of mine for a while. I only recently started recording my gas mileage as I have needed to drive more often, and I'm getting anywhere between 8-10mpg. Its a stock Olds 307 vin Y. Mods are complete removal of emissions system, true dual exhaust, cat delete, flowmaster 40 mufflers, aftermarket air cleaner box, replaced air cleaner a couple of months ago, stock q-jet was supposedly rebuilt right before I bought it in July 2009. Very recently completely removed the emissions equipment and changed the valve covers with breathers (which were never put on by the previous owner when he removed the stock air cleaner box for some reason). I'm pretty dumbfounded to be honest, I periodically run Hy-Per fuel system cleaner or Seafoam but this really doesn't do much if anything for my MPGs. I realize going the speed limit and not punching it help. But I know these low compression smog motors can make way much more. My brother's old '86 Elco with the Chevy 305 got 19mpg on average. definitely something wrong
Thanks!

 

[pontiacgp]

I'd remove a plug or two to see if it's running rich....and what rear end do you have?

 

[CaliCuttie]

I'd remove a plug or two to see if it's running rich....and what rear end do you have?

stock 2.14

 

[pontiacgp]

if your doing city driving those gears will kill the gas milage....

 

[CaliCuttie]

if your doing city driving those gears will kill the gas milage....

i live very close to san francisco. consequently, I do a bit of driving with streetlights whether in or out of the city limits. would a 3.73 be better for city driving in that case?

 

[pontiacgp]

with the overdive tanny I think most would suggest 3.42. The carrier you have now will go as low as 3.08 gears

 

[RITTER]

As long as you aren't gassing on it from every stop the 2.14 gears won't hurt you (you have to drive it according to the gears really, it's not going to take off like a drag car, so don't try) :?
You said you have true dual exhaust? Is there still an o2 sensor in your exhaust? Are there any wires pluged into your carburetor? Sounds to me like it is all carburetor/fuel issue.

I have had plenty of Regal's with the stock drive-train and beat on them and never got that bad of mileage.

 

[CaliCuttie]

As long as you aren't gassing on it from every stop the 2.14 gears won't hurt you (you have to drive it according to the gears really, it's not going to take off like a drag car, so don't try) :?
You said you have true dual exhaust? Is there still an o2 sensor in your exhaust? Are there any wires pluged into your carburetor? Sounds to me like it is all carburetor/fuel issue.

I have had plenty of Regal's with the stock drive-train and beat on them and never got that bad of mileage.

as far as I know there's no o2 sensor. like I said I delted the emissions system. There's the two wires plugged into the carb. I'm assuming one is providing the electric choke just don't know which. Should I be concerned with spark plugs, spark plug wires, fuel filter, etc?

 

[86_olds]

As long as you aren't gassing on it from every stop the 2.14 gears won't hurt you (you have to drive it according to the gears really, it's not going to take off like a drag car, so don't try) :?
You said you have true dual exhaust? Is there still an o2 sensor in your exhaust? Are there any wires pluged into your carburetor? Sounds to me like it is all carburetor/fuel issue.

I have had plenty of Regal's with the stock drive-train and beat on them and never got that bad of mileage.

as far as I know there's no o2 sensor. like I said I delted the emissions system. There's the two wires plugged into the carb. I'm assuming one is providing the electric choke just don't know which. Should I be concerned with spark plugs, spark plug wires, fuel filter, etc?

i would remove on spark plug i guess if it running rich they should be wet

 

[pontiacgp]

As long as you aren't gassing on it from every stop the 2.14 gears won't hurt you (you have to drive it according to the gears really, it's not going to take off like a drag car, so don't try) :?
You said you have true dual exhaust? Is there still an o2 sensor in your exhaust? Are there any wires pluged into your carburetor? Sounds to me like it is all carburetor/fuel issue.

I have had plenty of Regal's with the stock drive-train and beat on them and never got that bad of mileage.

as far as I know there's no o2 sensor. like I said I delted the emissions system. There's the two wires plugged into the carb. I'm assuming one is providing the electric choke just don't know which. Should I be concerned with spark plugs, spark plug wires, fuel filter, etc?

i would remove on spark plug i guess if it running rich they should be wet

or black