Originally Posted by spartan72
The check engine light works fine. It comes on when I turn on the engine for the first few seconds and Ive got an entire led setup so it is super bright. Im still playing with it all. I checked the exhaust and nothing smells out of the ordinary. I have noticed a very low idle if that helps any in diagnosing it.
Ok, so if the exhaust doesn't have the faintest small of gas at idle, put it in neutral and smell for it running rich as someone else revs the engine. Also put your hand in front of the tailpipe to feel if there are any "pulses" in the exhaust. If a cylinder isn't firing right or has a significant problem you should be able to feel it in the exhaust every time that cylinder fires. If everything is good, it should feel like a steady, even, slightly vibrating stream of air.
Have you checked for a fuel line or gas tank leak yet? At 8 mpg I would really expect the exhaust to smell rich like gas. (Is there any chance someone else has been "using" your gas without you knowing? Reset the tripometer and put baby powder on the gas cap/cover to alert you to tampering).
If all of the above checks out ok, the next thing I'd do is pull the plugs and to see what they look like (take pictures and post them, nothing the cylinder numbers). While you're at it check that you have a clean air filter and a O2 sensor (check visually, are you running an oiled air filter?).
You can also take a multimeter and check the resistance of the spark plug wires while you're at it. Write down the resistance of each wire in Ohms and then divide that number by the length of the wire. They should all be within 5-10% of each other. If not, replace them.
Running low at idle is interesting. Sounds like there's a restriction somewhere (intake or exhaust), the ECU is getting a bad airflow reading, or you're getting incomplete combustion in a cylinder.
When is the last time the fuel and air filter were replaced?