worn pistons????

[bmcgirk2004]

well my car runs fine until i shift to third then it starts to ping or rattle real bad and its louder and worst in fourth but first and sencond its fine does anybody have any ideas what it could be i have no idea and also in first and sencond it feels fine but third and fouth feels like its lacking horsepower.crapola

 

[BlackVert]

how long have you had the car? sounds like it could use a tune up:

oil change
fuel filter
dizzy cap and rotor
clean the maf
change plugs and wires
check for vacuum leaks
sea foam
injector cleaner