Engine Performance problem
1998 Audi A4 6 cyl All Wheel Drive Automatic 83000 miles
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Hi Pros, I have a 98 Audi A4 2.8 with a little over 82,000 on it. When the car is running and I have the sunroof open especially, there is a strong odor of raw gasoline that enters the cabin. Also the car is not getting good gas mileage, maybe about 14 mpg. I have changed the Gas Cap, Fuel Pressure Regulator and EVAP Canister Purge Valve. This week I will be changing the Fuel Filter as well. I don't know what else to do or look for. Appreciate any help I can get at this point.

Look around the injectors and at any fittings under the hood.IF you smell fuel, there is probably a leak and it needs to be found. Any check engine light? wondering if it is just running too rich instead of leaking. When was the last tune up? does it feel like it is missing at all?

Dealer said injectors are fine, car does have a bit of a rough idle. The CEL is on but the dealer said it was due to a bad Coolant Temperature Sensor that I see no sign of being bad. I will be doing a tune up this weekend inlcuding all filters plugs & wires. What tests can be ran to determine if the car is running too rich?

Normally the PCM will store a code that says too rich, but if the coolant sensor is bad, that will also cause the problem

A bad coolant sensor will cause what problem, the gas odor, the car running too rich or just the CEL. The CEL is not my main concern, the gas odor is.

If you don't have an actual fuel leak and the engine is running rich the CTS could be the cause if it doesn't switch from open loop mode meaning the computer will constantly be giving the engine fuel when not needed.

I strongly recommend have your fuel pressure checked. Could be a bad fuel pressure regulator or a clogged fuel return line overpressurizing it-excessive fuel pressure.

Running rich should throw out a code P0172 and/or P0175. Typical symptoms of an engine that is running rich (too much fuel, not enough air) are poor fuel economy, elevated emissions (Carbon monoxide or CO), and engine may have rough idle or surge condition.

Possible causes include a bad O2 sensor, excessive fuel pressure (bad fuel pressure regulator or plugged return line), leaky fuel injectors, dirty air filter or restricted air inlet, or a defective coolant sensor that prevents the engine management system from going into closed loop mode.