Fuel economy worse after tune up? Engine is a 2.0L Zetec.
Just performed standard maintenance on this car after buying it a month ago. Mileage was an unimpressive-but-passable 28 MPG on the highway. Changed oil the day I got it home, waited for other maintenance. Changed plugs, wires, and air filter. Mileage has now dropped to 24 or 25, and that's after changing my driving habits to be much more conservative. The first tank after the change was around 21 MPG.
Car idles rough while stopped in gear, and the belt is quite possibly needing to be replaced. It squeals quite loudly when I lock the steering wheel in either direction. On occasion I will also smell a hint of burned oil at a stop light, but cannot find a leak anywhere on the motor. I assume that since the reservoir for the power steering pump is directly over the exhaust manifold, there is a small leak from that. The engine is completely dry outside.
What am I missing? It runs strong and accelerates like a banshee (well, if banshees had 2-liter engines).