Why Am I Getting Bad Gas Mileage On A 1989 Ford Taurus 3.8L?
I know I shouldn’t pay any attention to EPA estimates, but others have reported getting between 17 mpg and 20 mpg in moderate city traffic. I am getting between 10 mpg and 12 mpg.
I recently replaced an Idle Air Control Valve, Serpentine belt, Exhaust Gas Recirculator Valve, and had my Catalytic Converters (all 3) checked. I don’t drive with a lead foot, I don’t start off the line too fast and I don’t come to sudden stops.
Anyway, I also ran a KOEO self test (uses 2-digit codes) and it came up with the left and right oxygen sensors detecting lean, and Fuel Pump Secondary Circuit Failure. That last one sounds bad, but then again I have one of those hidden fuel shut-off buttons inside the car on the floor next to the driver door, so it may have just saved into memory the fact that I used that.
When I took it to a muffler shop, thinking it was the cat converters causing a problem, they said that it’s not the cats and that they smell unburned gas. Maybe a leaky fuel pump or fuel line? Maybe the fuel injector? At this point, I have no idea, but I can’t afford to have bad gas mileage. Could someone help?
Tagged with: air control valve • catalytic converters • cats • circuit failure • city traffic • estimates • exhaust gas • fuel injector • fuel line • fuel pump • gas mileage • idle air control valve • lead foot • memory • mileage • mpg • muffler shop • oxygen sensors • self test • serpentine belt
Filed under: Ford Taurus 1986-1991
I have never liked th 3.8 engines that was put in the Ford Taurus .. . The 3.8 in general has always been problem child for Ford ..It is very hard to diagnose a car without having seeing it in person. Some of the 3.8 engines have 24 valves in them . The model is/ws marketed as the SHO model . Replacing the sensor is a good idea . Taurus improved after the 1999 models.. Most Taurus have the 3.0 engine which is a work horse . I wish I had a better answer for you . I would try to upgrade to a newer model if you can afford one. If you get another Taurus make sure the transmission has been replaced . The Taurus is well known for transmission problems. The 1993 through 1995 where the worst model that had the most trouble in Taurus line .
o2 sensors can cause bad gas mileage. replace plugs and wires also if u havn’t already done it. as far as the circuit failure it might b cheaper to replace the whole fuel pump. u can do it yourself in your driveway in a few hours..
First, I commend you for providing detailed information.
If in fact the O2 sensors are "detecting lean" then the response of the computer will be to send more fuel via fuel injectors operation.
The smell of unburned gas is further evidence that this could be happening.
You need to take it in to a trusted diagnostic capable shop. Fault codes only point in a direction, they are not the end of a diagnosis. The O2 sensor operation can be verified with the proper test equipment.
BTW: raw gas getting to the cat converters may lead to premature failure.
Your on the right track, I just put a bran new fuel pump assembly in my Grand Marquis 2001 and the mechanic said he put a complete assembly because even if he replaced just the pump I would be back later with leaks. He said this is a common problem with Ford fuel pump assemblies. It sounds like you are getting fuel but the return is leaking or not functioning.
Take this one to a mechanic and pay them to check it out, they will sometimes wave the this charge to complete the work for you.
Fuel mixture is mainly measured by coolant temperature, so make sure thermostat is not stuck open, usually driving down the highway in cool weather, guage should be around the center, if it stays on cold, change thermostat