'94 SHO is running rich...

[92StangMan]

For the past week I have been smelling gas inside my car and my mileage has been going down. You can also tell its running rich just standing outside as it's idling.

The car has 135k miles and have had no problems with the engine and have no clue where to begin looking. Is this common problem?

 

[frosho]

Have you pulled the codes? I wouldn't be surprised if an o2 sensor code were to pop up. Try it and see what happens. Here's the procedure-

http://www.shophoenixproject.com/eec/eec.htm

 

[itwonder]

Clean MAF, run KOEO and KOER test at shophoenixproject.com, check codes.