Shaking..and not shifting.

ohh god where do i start. the car just underwent a full tune up and it has 75000 miles on it its a v6.
First Problem:
The car seems to shake or i feel alot of vibration in the steering wheel when its in Drive and im stoped at a light or just idling but once put in neutral all the vibration goes away.
Second Problem:
This only happens when its at a Quarter full or less of Gas and no exageration it only happens When it reaches 1/4 full. Driving is not a problem but when i try to accelerate a little harder around 4000 rpm's or so the car bogs like its not getting any fuel and on two instances it has shot off on me and i was on the highway both times and its not pretty when ur doing 65 and u losse all power sterring and breakes.

I realy dont know what to do with this car.. if any one is nice and helpfull to tell me what would be wrong with the thing i would greatly appreciate it.

sell it and buy a s2000 or 350z

[Redog]

Idle problem not too sure about, could be a loose mount, plugs or wires not tight.

1/4 tank of gas problems, sounds like a fuel filter issue. time to change it out

[AGT]

Who did the tune up?

[super white alero1]

Sound like a tune-up issue. Ez method would be a a spray bottle of water squirt some on the wires while motor is running and check for arcs. If you see them then chances are the wires have a hole. Make sure the the wires are press completely in. especially on bank 1(firewall side). could possibly be that your fuel sender unit is defective, ie. not reading correctly. try parking on a hill facing down and start the car with 1/4 tank or less. If it cranks but don't start then it the sender unit that's faulty.
P.s.
Also can be your fuel pump is weak, at over 3000 rpm, if not enuff fuel is getting to your engine can cause that same issue, try WOT in 2nd gear and see if the issue is still there. If not then it may be your tranny.

thanks alot guys....for ur help...i changed the fuel pump and the not shifting problem wiht the hesitation went away...the only problem left is that the car start vibrating when it reaches operation temperatures.

[antichrysler]

i had that same issue way back when... stuff like fuel injector cleaner always fixed it for me