1.8 with about 155k on it.
Some time in between tank fill ups not too long ago my gas mileage suddenly dropped from about 29mpg to not much more than 22mpg. And it wasn't a gradual decline in mileage.
It's also having trouble holding an idle sometimes after starting the car after it's been fully warmed up. It will unhappily struggle around 500rpms unless I hold it up by pressing the gas pedal.
Only does it on warm engine start ups and goes away after a couple minutes and doesn't happen while driving.
Also, I filled it up yesterday and had a fuel smell in the cabin for a while afterwards and had to keep the window cracked open. Not sure if this is related or if I accidentally spilt some gas on myself.
Plugs and wires are fine. Fuel filter is less than two years old.
What could be causing this?