Ford Touring

1998 Ford Touring Fuel System Tuning  Always

i replaced my spark plugs when my mpg dropped to 11 it went back to 12.5 i used to get 17 i was told pressure regulator was cause is this true. im working on lioncoln towncar

your pressure regulator is a possible culprit.
You said you did the plugs what about the wires?
If I were you, I'd start throwing cheap and/or quick'n'easy parts at it 1st. Fuel filter, O2 Sensors, check for vacuum leaks and proper fuel pressures (including the Charcoal Canister Purge System and the Fuel Return System), clean the MAF Sensor, change the MAP Sensor if you haven't already, check the ignition system (the coil and the OptiSpark may need to be replaced). Anything you haven't changed since you bought the car should be considered a possible problem.
Check this out:
Did you overfill your crankcase with motoroil? I only put 4.75 Q of Mobil1. Overfilling means that your entire crank has to drag itself through oil. Same thing with your tranny.
Check your alignment.
See, if you are getting 11-12 mpg, and your car isn't throwing any codes, the odds are you have more than one thing wrong.