I hit the im not going to run right Wall

94 s10 blazer 4dr 4wd w vin . picked up out of jersey drove back down cylinder 3 .
due to spider and fuel kit. replaced both.. added new distributor ,plugs, wires... set timeing , fixed vacuum leaks, cleaned egr , new map sensor . threw my used /new cat in and passed emissions and spection.
now the problem is it still has a miss and rough idle. pop the hood and apply some throttle and hold and she goes to correct rpm then drops slightly and surges .
was also going to put my new o2 sensor on from my retired 94 but it was a 3 wire and this blazer is a 4 wire heated o2 so no go. im used to dealing with these motors . me and my brother/mechanic and me are stumped . also fuel pressure is good .
is there something i missed or does anyone have some helpful input thanks any help much appreciated i'm not wanting to go to STEALERSHIP!
i have access to a shop and some diagnostic tools and two hands Please help



also have a 2-5 sec delayed start witch is odd to me my old one started the instant the starter engaged i would love to fix this tooo

 

Check to ensure your engine grounds are all proper. Also, when you check timing, does the mark jump around sporadically?