I have a 2005 Nissan Altima. When driving if i hard acccelarte the rpms start to serge and the car jerks really hard and it wont get ove about 20 mph. Does anyone have any idead as to why this happens?

I am almost positive this is a cyliner misfire issue. It sounds fairly severe if it wont even reach 20mph. This could be an electrical issue (spark plugs, coils, or wires could be faulty) or an air/fuel problem (clogged fuel injectors. There are too many possibilities for me to tell you what exactly the problem is. I would suggest taking it into a shop atleast for a diagnosis on the problem. Try not to drive it, because driving without all cylinders puts tremendous strain on the crank shaft and that is an extremely costly problem.

well if i easy on the gas slowly it does fine and holds speeds of 65 or better no problem. Just when i do a hard fast accelartion

Then I would say it could be your drive shaft, or your U-bolt going bad. A driveshaft is not cheap so try to rule out the U-bolt first.

the motor will also surge if you rev the motor in park as well.

does anyone knw if a factory 28185-8j100 radio wit fit in place of a 28185-8j200. all the plugs look the same. just want to get the busted 6 disc out and replace it with i single disc player. thanks