Hot start idle sputter / bucking

Ok so I picked up a 1999 5 speed 4dr 4x4 4.0L for 2500$ a few weeks back, and this engine has had the exact same problem from day one. I am under the impression it sat for an incredible amount of time before I purchased it. :doh: I searched all over and couldnt find a previous thread on a problem as specific as this. Anyway to the problem.

When I start this thing up lets say after running it for 15 minutes then parking going into a store and then walking back out to go elsewhere it will crank over just fine run silky smooth, and then out of no where at idle the darn thing will just start going nuts but when I give it some power it will stop and rev up fine, then it will go back down to idle and keep doing it (sputtering real hard) until it finally go away after a minute or so and won't return until the next time it turns on. It has thrown the check engine light but then it simply goes away. The really annoying thing about it is it's manual so if it catches me off gaurd when im accelrating from a stop the jeep will buck so hard I feel like im gonna get thrown out of my seat. On a cold start it hasen't ever done this to me.

Now for things I have looked at about the problem or have tried to fix.
I have seafoamed the intake manifold.
Ran alot of injector cleaner / and Lucas fuel injector cleaner and conditioner
Checked all the plugs
changed oil etc etc

Possible ideas I have
New plugs wires cap and rotor
New injectors
Fuel pump
Fuel Filter

I dont have much money, i'm a student so I couldnt progress more from there. Any input is greatly appreciated.

Take to advance have your cel scaned. See what codes are stored then go from there. My 98 has cel light on had it scanned code0505 I think bad iac control vale. it wont idle until eng warms up.