HELP!!! 99 cavalier 5spd 2.2 stalling

[RagingFetus]

hey guys. i have a 99 cavalier, manual, 2.2... car has been idiling poorly and lagging in acceleration in every gear. now its stalling when slowing down for stops. if in traffic or coming to a stop sign or a turn as soon as i hit about 5mph it shuts off. it will start right back up and as long as i have it in 1st gear and hit the gas right away, i can drive. if im at a stop and i continue to give it gas, in gear or in neautral it will not stall. a few months ago i had the check engine light come on for the MAP sensor, but it went right off 2 days later and nothing has come on since. when im stopped if it doesnt stall, the engine's rpm's will go way up and then way down like it wants to stall. sometimes when it revs way up it will hold there for 5 secs or so till it goes back down. PLEASE HELP!!! thanks, Jasen

[shakewell]

Check for vaccuum leaks. Follow any hissing noises while the engine is running and look for any cracked or broken hoses. Go from there.

[i3o2Matt]

have the fuel filter/ spark plugs/ wires been changed ever?

[RagingFetus]

UPDATE!!!
I disconnected the MAP sensor and have been driving with the MAP sensor disconnected. The car has been running 100 times better. idles a lil rough, but nothing like with the MAP connected. acceleration is all back to normal. when i come to a stop and the car decellerates the rpm's flatline at about 1200 for a few secs before finally going to 0. my question is i cant get a new map till 7 days from now. can i continue to drive with this sensor disconnected? i have a 99 cavalier and my car doesnt have a MAF, just a MAP. any help would be apprectiated. ty in advance.
Jasen

[RagingFetus]

i am now getting a mil for a bad crankshift position sensor. i am thinking this is what is causing the rpm's to not go right down when coming to a stop. but i know the sensor is not really bad, has to be in conjunction with the MAP being disconnected.

[shakewell]

It's hard to say. I wouldn't think that the MAP being unplugged would goof the crank sensor, but anything is possible.