These cars jump from neutral to in gear for autos so that's normal. Depending on how many miles are on it, yes plugs, coil/packs, fuel filter, motor/tranny oil change, rear end check. A tune will help with gas mileage, you can get a tuner from American muscle and have three different kinds of tunes.
2003 GT - full bolts ons, suspension, and drag radials
1998 cummins - 150hp injectors | FASS fuel kit | 4" straight pipe | 5" lift | BHAF | 20" wheels | edge juice w/ attitude | built auto trans with stall | closing in on 900tq | bigger turbo soon..
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