need some help

[jaw240]

I recently bought a 92 240 fastback and it was running great for about the first 3 months. My car has 220 000 k on it and is starting to give me some problems. The things i have noticed wrong with my car are: studdering and shaking while idleing(idle speed jumps low as 200 and as high as 1300 rpm), major loss of power only after the engine is hot(when i start in the morning if feels like a true racer but after the day goes on and my engine gets hotter i go slower and slower) it starts to feel like driving at higher rpm makes no difference in speed, and finally i am getting a firecracker like smell in my cabin occassionally. Also I have had my car for 6 months and i have routinely checked and changed the oil, checked my oil and air filters, tested my distributer and put new ngk spark plugs in. PLEASE HELP

<240power> <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/sneaky.gif" border="0" valign="absmiddle" alt=':pissed:'> rockin site.