starting/engine problem?

[roxsox10x]

Hope everyone is having a fun (and safe) memorial day weekend.
Alright, mines started with car problem. I had a problem with starting my ex this morning. I tried to start it and it made a kakakaclunk noise and stalled. So I started it again and it made that noise again but this time it didn't stall. Instead, it was reving up and down and it looked like it was going to stall again but didn't. The rpm was still shaky and then all of a sudden it started reving on its own going to 3000 rpm going back down then 3000 rmp and going back down. Finally it went back to a little under 1000 rpm and stayed there. I could feel the engine shaking and the shifter was shaking as well (shaking harder than usual that is). This is all happening in neutal as Im jus sitting there just letting it warm up and thinking maybe some water got under the hood maybe? It was raining last night (im in California) and it was cold this morning so I figured that might have something to do with it. I drove it to the store less than 5 mins away and it was fine. When I started it , it made the nice normal sound like it usually does but then as it was warming up the rpm and engine became shaky again but it wasn't that bad. I made it home. So I started the car again 30 mins later to move it and again starting it was ok but once it started the engine became real shaky and the rpm is going up and down on its own looking like its going to stall. There is also a hissing noise.
I know its memorial day weekend but I figured I would just put this question out there. So does anybody know what's going on with ex? What do you think is wrong with it or has anyone had a similar problem. Maybe its just because of the rain last night? Any help/suggestion is greatly appreciated.
Btw, I have a 98 manual transmission 5 speed 4x2 explorer sport 2 door 4.0 ohv (I think its ohv). I jus bought the car last month from a private party.

 

[aldive]

Did you check the IAC?

 

[roxsox10x]

Thanks for the advice. That's probably the first place I should check because of the idling problem.

I haven't checked anything, I just left the car there becasue I didn't want it to ruin my weeekend. Though, starting it is a bit better now as it doesn't idle as drastically. The car is not as shaky as before also. That's my main concern because the motor is literally shaking hard, that ex is rocking, and you know the ex is a pretty big car.

I was going to say that the check engine light didn't flash up on the dashboard but now I can't be too sure because the seatbelt lights doesn't flash sometimes. I usually start the engine and figget around and then put my seat belt last so the light should be on but it wasn't. At first I thought it was good that it didn't come on but then I realized that if that light didn't come on then maybe the others didn't either. Though the parking brake sign stays on until I release it though.

I also forgot to put that I didn't drive the car in about a week. Do you think that might have been the problem? That I haven't really driven the car other than moving it a few feet because of parking (street sweeping)?

Any thoughts? Anyone?