Hi,

I have a 2004 Altima 2.5 S.  I have been having a problem when I step on
the gas pedal.  The gas pedal has become extremely weak and sensitive.  I
have to keep my foot on the gas pedal in the same position in order to
keep my car at a constant speed on the road.  As soon as I lift my foot
off the gas pedal (with the slightest inch) my car loses its speed
constantly.  It is beginning to create a problem for my leg and foot
because I have to keep my foot in the same position for a long time.  My
gas pedal was not like this before.  I'm not sure if I need new spark
plugs or if its a problem with my fuel pump or a problem with balancing my
wheels.  My fiend told me it may be a problem with my throttle.  Could
anyone please offer me some advice on what I could do or what it maybe?  

Thank you very much.