13.5 mpg?

sd88supra · 12-02-2006, 03:09 AM

i usually get about 320 miles to the tank (before going back to fill up), this last time since i filled up i got 210 miles! at first i was skeptical, i had driven 205 miles and my needle was below the empty mark and the low fuel warning light came on. so, i went to the gas station and filled 'er up. bought 15.5 gallons, which sounds about right (my low fuel warning light comes on around when im down to about 3 gallons). also, my gauge just dropped quick. it wasnt like the usual where it stays on full forever then starts going down and the needle dropss at the last 1/4 tank. it just dropped constantly. i looked under for fuel leaks and didnt find any.

so, im thinking my car is running to rich although i dont have the running rich symptoms. did a diagnostic and got my usual egr code (71). any ideas?

Bman86.5 · 12-02-2006, 03:56 AM

hey i had the same problem with my winter car (1990 toyota camry). There was a bunch of small leak on top of the gaslines and as the fuel pump is running with the car on, little bit of gas leaks slowly out and for me went unnoticed till the second time my mpg went in the shitter. So try and look and feel ur gas lines as the car is on to preasurize the lines.

sd88supra · 12-21-2006, 04:58 AM

I had my mechanic check the lines, and he said they seem to be fine. Also, when I go to put in gas, I hear a fairly long hissing noise, from the pressure in the fuel system. My question is, how much is too much? I had heard the hissing noise before, but very little. Now its longer and louder, which makes me think there's too much pressure in the fuel. What can contribute to this? Or is it a bad fuel/air mixture?

I don't have the running rich symptoms but I can sometimes smell unburned fuel. With the exception of slight hesitation/jerk at 2000 rpm (when keeping that engine speed) my engine runs very smoothly. BUT, my gas mileage is ranging from 10-13 mpg

Staceman · 12-21-2006, 02:22 PM

OK, I'm new to Supras. BUT, I am Very familiar in Toyota 4 and 6 cyl trucks.

With those, if everything seems fine, but MPGs drop considerably, replace the O2 sensor. Might not even throw a code, replace it anyway. Your system is adding more fuel to the mix because it isn't reading right anymore.

Best place for a (real - OEM) Nippendenso O2 sensor with best price.....

SparkPlugs.com.

Other sensors from generic parts places sensors' aren't long enough to really get into the exhaust stream for a good reading. Go Denso man!

Bman86.5 · 12-21-2006, 10:44 PM

thats a good idea with a bad O2 sensor the engine might stay on choke and lower the mpg

12-02-2006, 03:09 AM	#1
sd88supra 3" Exhaust Join Date: Oct 2005 Location: San Diego, Ca Posts: 190	13.5 mpg? i usually get about 320 miles to the tank (before going back to fill up), this last time since i filled up i got 210 miles! at first i was skeptical, i had driven 205 miles and my needle was below the empty mark and the low fuel warning light came on. so, i went to the gas station and filled 'er up. bought 15.5 gallons, which sounds about right (my low fuel warning light comes on around when im down to about 3 gallons). also, my gauge just dropped quick. it wasnt like the usual where it stays on full forever then starts going down and the needle dropss at the last 1/4 tank. it just dropped constantly. i looked under for fuel leaks and didnt find any. so, im thinking my car is running to rich although i dont have the running rich symptoms. did a diagnostic and got my usual egr code (71). any ideas?

12-21-2006, 04:58 AM	#3
sd88supra 3" Exhaust Join Date: Oct 2005 Location: San Diego, Ca Posts: 190	Update I had my mechanic check the lines, and he said they seem to be fine. Also, when I go to put in gas, I hear a fairly long hissing noise, from the pressure in the fuel system. My question is, how much is too much? I had heard the hissing noise before, but very little. Now its longer and louder, which makes me think there's too much pressure in the fuel. What can contribute to this? Or is it a bad fuel/air mixture? I don't have the running rich symptoms but I can sometimes smell unburned fuel. With the exception of slight hesitation/jerk at 2000 rpm (when keeping that engine speed) my engine runs very smoothly. BUT, my gas mileage is ranging from 10-13 mpg

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12-02-2006, 03:56 AM	#2
Bman86.5 Stock Join Date: Nov 2006 Location: North Tonawanda Posts: 13	hey i had the same problem with my winter car (1990 toyota camry). There was a bunch of small leak on top of the gaslines and as the fuel pump is running with the car on, little bit of gas leaks slowly out and for me went unnoticed till the second time my mpg went in the shitter. So try and look and feel ur gas lines as the car is on to preasurize the lines.

12-21-2006, 02:22 PM	#4
Staceman Intake Join Date: Nov 2006 Location: Phoenix, Az. Posts: 48	OK, I'm new to Supras. BUT, I am Very familiar in Toyota 4 and 6 cyl trucks. With those, if everything seems fine, but MPGs drop considerably, replace the O2 sensor. Might not even throw a code, replace it anyway. Your system is adding more fuel to the mix because it isn't reading right anymore. Best place for a (real - OEM) Nippendenso O2 sensor with best price..... SparkPlugs.com. Other sensors from generic parts places sensors' aren't long enough to really get into the exhaust stream for a good reading. Go Denso man!

12-21-2006, 10:44 PM	#5
Bman86.5 Stock Join Date: Nov 2006 Location: North Tonawanda Posts: 13	thats a good idea with a bad O2 sensor the engine might stay on choke and lower the mpg