Guess I'll chime in also. Last month I had the spark plugs, spark plug wires and PCV (?) valve replaced, 2 weeks ago I drove from Las Vegas to Phoenix/Gilbert, Arizona (325 miles) with the A/C on I got 34 MPG, highway, both directions. Here at home I only drive streets (NDOT is working on all freeways so they are nightmares and its quicker on the streets) and I am averaging about 29 MPG. Both figures are up about 5MPG since I had the work done. Oh yeah, by the way, I also have about 1300lbs worth of stereo in the vehicle so I guess I am very happy with the mileage.