It probably needs a new clutch.
maybe
yes
behind the drivers seat.
it could be your timing.
If you're asking about the gas mileage that would depend on the engine. Would it be stock or are you looking to add performance enhancements? A stock engine should get around 18 to 20 mpg with a 3.55 gear or around 15 with a 4.10 gear.
Torque convertor could be defective siezed up.
check clutch slave cylinder
The transmission. or clutch if it has one.
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It might be the clutch.
I have used 2 different methods. If the cam cover is off you can place a large screwdriver in the hole of the chain sprocket. Then you could put it in 2nd gear and lock the brakes or have some one step on the brakes. Both worked for me.
you must have a clutch. put in second gear and push it and pick up some speed ,then engage cluch and put in second gear and release clutch ,make sure u have the key turned on.