1slicktwo4oh

Alright Zilvians got a problem w/ my 240, where are the engine gurus i need your help. So my KA gave up on me the other day on the way to work...I was cruising down the 60 freeway when i started to notice my RPM needle jumping erratically, it did that for about a minute before the car started jumping in relation to the needle. 2 minutes later it started slowing down, I had my foot on the gas and it didnt matter the car started to slow down it would go past 40mph until if finally stopped, ditched me off the 605..
So i got it towed to my job. The car turns on then turns right off. I can keep it on by revving it but it still wont rev past 3000rpm, if i floor it it will pulse from 2-3k rpm and backfire. A co-worker knew a mechanic so i had him check it out he told me it might be my coil, or ignitor chip. I was gonna get sum used ones but since its for my daily i opted for new parts. $180 later same shit. So know im hearing it might be my TPS, OR MAF OR my DIZZY....no clear answer, ughhh frustrating, So before i go spending more ca$h, has anyone had this happen to them or anyone have sum good knowledge on SOHC KA's, got try and fix it fast. I have a feeling it something simple cause the motor ran STRONG before this, so im trying to fix it myself before having another mechanic have a whack @ it