Nope, it's a new problem. I'll break down the sequence of events a little better:

I bought the car last year, already swapped. It was basically a stock swap, with only the fuel pump and FMIC. I added everything else, including a GTiR T28 turbo. Didn't like the power curve, so recently I swapped it out for a BB S14 T28. Also replaced my NGK iridium plugs with fresh V-Power copper plugs. Boost is set with an HKS actuator.

Since then, the car hasn't run quite right. At first, it wasn't that bad; it would just stumble a little bit in the middle of the rev range, but would still pull nice and hard once it got past that. Idled perfectly fine on startup. It's gotten progressively worse, to the point it's at now where it barely goes anywhere and runs rough/stalls on startup.

Knock sensor cable is shielded properly; as best I can tell, it's just like it should be according to the FSM. I have continuity between the shielding wire (sticking out in this picture, on the right side) and the ground pin on the connector on the left side of the picture; also have continuity between the signal pin on the connector on the left, and the pin on the connector on the right. No cross-continuity (I don't know if that's a word, but basically, no shorts in the subharness). It does look like shit, but it seems as though it works fine.


I recently installed a Nismo FPR as well, I forgot to mention that. Pressure's at 36/43 with vacuum line off. I haven't checked the MAF.

It hasn't been tuned. But it ran perfectly fine with the GTiR turbo and no tune (albeit a little peaky). I suppose the ECU could have gone bad, but the thing that gets me is, the problem has been getting progressively worse; it wasn't that bad to begin with.


ALSO worth noting: It boosts fine, just doesn't go anywhere. Turbo has almost 0 shaft play. Haven't gotten any oil in intake piping, and I haven't noticed any smoke coming from the exhaust (signs of something like a blown ring).