Intermittent loss of power, misfire during boost

[Spoolin92GSX]

Posting here because it doesn't really fit anywhere else, mods move if you feel appropriate. So here's the deal, I picked up this 97 GST a couple months ago and have been rehabilitating it since then. All boost/intake leaks have been eliminated except for a very small leak at one injector. Plugs have been replaced+gapped, stock fuel system, no tune, MHI 14b with an "aftermarket" adjustable WGA.

What's happening is, once the car is at operating temp I can feel a subtle loss of power/misfire start under normal driving conditions. When this happens, I am able to build boost up to ~13psi but with heavy misfiring (akin to boost leaking) and no power. Now, when I don't feel the cruising misfire, I can stand on the accelerator and it will struggle to build even 5psi of boost, but the engine will remain smooth.

I'm trying to get an idea of what could be causing this before I go diagnosing in the wrong areas, anyone have an idea of where to start?

 

[1990TSIAWDTALON]

Leaky Wastegate??? My actuator went out and I had some similar issues. Just throwing it out there. Just check it and then check it off the "list".

 

[Spoolin92GSX]

Yeah, I don't have much faith in the actuator that's on there right now but I don't see it behaving intermittently like this is.. Still something to check regardless though.

 

[boosted97RS]

Just curious, but what is your vacuum at idle?

 

[Spoolin92GSX]

Vacuum at warm idle is right around -22inHg.

 

[c2ypt1c]

It only happens at operating temp? Almost sounds like the coil pack...could be the plug wires as well. When were they replaced last?

 

[Spoolin92GSX]

Yeah I'm suspecting plug wires.. Honestly don't know when they were replaced last so I'll go ahead and test the whole ignition system and start replacing as needed.