Toyota Repair: Misfireing\Rough idle, iridium plugs, toyota paseo

Question
My car is a 93 Toyota Paseo,with a 1.5 liter DOHC 4 cylinder engine.I just installed pacesetter headers.My car ran perfectly the fine the first day i had them installed,no problem whatsoever.The next day i went to go drive it,i went to step on the gas,full acceleration and the car goes mabye 10-15 miles an hour,and slowly sarts to pick up kind of jerking,like the spark plugs aren't fireing,so i changed the spark plugs to NGK Iridium plugs and it took care of the acceleration problem,but the car sill Misfires really bad when you come to a stop,so bad it causes the RPM needle to just go crazy,and if you sit there long enough the car will just die.I changed some other things,like the fuel filter,the fuel line,ran additives through the gas,no change.So finally i decieded to take it to a shop,Big Mistake!.We take it to the shop,first they tell us the fact is that my headers dont have an EGR Hookup,and that was causing a vaccum leak,but they said they could  turn the Egr off and it wouldn't do that anymore.Also during the course of that said my plug wires were bad,witch i replaced less than 5 months ago,also apparently my cap and rotor was bad also.And they said my 13.00$ apiece spark plugs were causing my car to run worse,so they replaced them with 4.00$ apiece Denso's and said my car was running better.So 400$
later we go to pick the car up,i drive it away no misfires nothing?about 5 minutes later it starts misfering and goes back to the problem of full acceleration,no power?whitch it wasn't doing before,my car ran worse not better?so i take it back to them and they charge me another 100$ and put on a scope and they say My o2 sensor is what is causing the problem,the computer isn't reading it?.I spent this money to replace these parts that they said were bad,and they said my car would run better,but it runs worse?Anyway i put my old plugs back in and once again it took care of the acceleration problem so at least its drivable,but still misfires badly?I really dont think the EGR or the o2 sensor has anything to do with this problem,because from what i hear all the EGR does is lower emissions?.The car runs fine on the freeway,its only town and stop an go driving that i have trouble with,have done compression checks on the engine,and its in great shape?.The last thing i could think of is there is something wrong with my fuel injectors.i feel like i was ripped of by the by the shop,i dont know what to do,i cant afford to take it in again,so im hopeing that i provided enough info so that help?Please?.Mike Phillips.  

Answer
1st check the EGR your self and this is what it should do, unplug the hose at the EGR, plug up a long enough hose to it so you can draw a vac on it with the engine runing if it dies then its fine. to make sure its not sticking open while its runing,tap( I tell you to tap, me I get a little carried away, It works though, haven't broke one yet, you can clean this,I would remove it anyway just to make sure it didn't get a clung of carbon in in it, just me)  on it and see if it smooths out.  Must not have been a Toyota Dealer because repairs are good for a year,look at the coil real good  to see if it has a crack this is one of the most missed things I see.