I checked everything. I am getting a very crappy mileage, about 20mpg in city driving and about 24 in highway. Changed O2 sensor, checked timing, cleaned throttle body, changed plugs, cleaned IACV and AAC. I have a slight leak on the plug wires but I don't think this would cause so bad mileage. Any more suggestions? Thanks Sato 94 Nissan 2000GSR 70k miles.