please help!!!

Alright i see that people seem to be getting this alot after reading other threads now i have a 91 cav z24 and lately my car has been acting weird when i pull up to intersections the rpm goes down to about 400 then it revs by itself while im stopped up to about 1000 it goes back and fouth sometimes stalling out . also im finding when i accelerate only when my car is "warmed up" its sluggish and seems to suck alot. possible on an unrelated matter now my engine light is on. i have had the problem somewhat the same previously but seemed to be fixed by the change of ignition wires and plugs which was about a month or 2 ago. anyhelp would be wonderful thanks

Unrelated matter the engine light is on?

Comon bro, that is your problem and IS related. Go to autozone and get the codes scanned for free to find out what the problem is.