I'm working on a friends 86 GN. Problem is when I go WOT with it and it hits second, the car acts like you just shut the key off and then back on. It does this several times and if you stay in it, the power is not much more than an idle. It doesn't bust up or backfire, sort of reminds you of hitting the speed limiter in a late model vehicle. At first it only did this above 15 lbs of boost. I thought of valve springs as it has no codes and fp looks good. The springs was a little weak when I tested them so I replaced with a heaver spring. However I'm still having the same results. I have swapped coil pack/module with a known good working one. I swapped ECM with a good known working one. I unplugged the cam sensor while it was running and still the same thing. I removed the waste gate rod to where it only had about 3-5 psi of boost and when it hit the upper RPM's, it acted up. I've replaced the plugs and gapped them at .032. I've checked fuel pressure and I'm getting 1 psi to 1 psi of boost. The only thing that I have to data log with is a old school OTC 4000 which has a very slow update rate however I've logged several runs and nothing looks out of the ordinary. MAF is staying maxed out at 255 until it pretty much just shuts down. It does have a aftermarket LS 85mm MAF sensor and translator. Someone has cut the factory fuseable links and spliced in new wires with fuses so I think this is going to be something to look at. I'm also wondering if the crank sensor could be loosing it's signal but you would think that you would see the RPM go squirrely when I data log. I've looked at battery voltage while data logging and didn't see any huge fluctuations. Normal driving seems to be ok however at light throttle, it does seem to have a slight miss. Also the car seems to idle ruff.