I really need help here guys ok so I have a 87 N/a check compression was consistent at 93, changed out the cooling system, changed brake finally got it driving correctly and then for the longest it was like my car hit a wall at 1500rpm when I tried to Rev past it legit would not let me. Finally changed the fuel filter put 93 in and did some chevron tacron ran good for about a month then a few days ago started doing the same crap again but now my car is able to push past this so on so wall but was driving and would stutter and buck at around 4200 but sometimes ill be driving and it goes fully almost redline no problem, ealeir on before changing fuel filter would being going around 80 and would be at around 4500 would legit surge and buck, after changing didn't do it anymore, also check fuel pressure read 42 which is good, started doing the same crap again the other day Heres a video of what I mean by the "wall" bucking stutter thing if any of you know what this could possibly be it'd be great to have a reply thanks!

 

Video of the problem^^^

 

Check your intake and make sure no bolts are loose. Im still a noob, but when I was trying to get my 86 N/A's engine to come back to life, the last hiccup I had was that it would start and then immediately die. Turned out my intake had a couple of loose bolts and wasn't fully sealed. Started right up once I tightened them. Im theorizing here but it could be that something similar is happening to you but it only barley jimmies a little loose for just a moment while vibrating, looses the seal, stabilizes, gos back up in rpms and just keeps repeating until it manages to push above the threshold. Im probably talking out of my *** but it would be a pretty quick thing to check. That and your vacuum lines.

 

Drop and clean your fuel tank. Change the filter sock on your fuel pump and change your fuel filter again. If the problem continues after this get your injectors cleaned and flow tested.