92 sedan deville with some problems
 

i have had the car a few years now and just in the last 6 months or so when i give it gas even alittle the accelerator seems to stick i would have ot tap the gas pedal for it to stop but not it doesn not always work ??
also when i'm either at a light or even stop sign you can feel the rpms go up and down sometime so high i have to really hold the brake and other times it drops so low it kills the engine ?
any idea what it is
thanks