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Love hate relationship, help needed

89 R32 GTR 35k miles, has a misfire at idle that gradually gets worse as i drive the car for a long distance. Doesn't break up under load & seems to run well. I have been ripping my hair out trying to figure it out. I have given up & decided to reach out to the SAU community for any help. Below is what i have done to try and subside the infamous misfire. Thanks in advance for anyone thats willing to help me diagnose this turd.

 

Heres a list of everything i have done. Motor is stock other than exhaust, filter pods & ls2 GM coils.

New oem nissan 02's
New oem TPS
Used but cleaned & tested oem Injectors
Battery
Fuel pumps
Fuel filter
Re-sauder mafs, borrowed known working mafs
GM coil conversion. Reinstalled original coils, no change.
Borrowed ECU
checked all sensors on scanner, ecu talk & snap-on modis. Checked cylinder balance & hooked up oscilloscope. Also ran an injector balance test.
Replaced chassis/motor/battery ground cables.
Spark plugs @ 0.8 gap & 0.7 gap. Tried bcpr7eix & copper core ngk.
New temp sensor.
Sprayed non chlorinated brake cleaner everywhere looking for vac leaks.

Compression test was 150 psi across the board.

 

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Have you tried unplugging coilpacks and injectors one at a time to see if there is a problem there? Yes I know you have done the coils and injectors but perhaps there is a wiring harness issue.

Do you know what AFR's the car is running when it hits the issue?
Base timing OK?

Base timing set at 20. Timing doesn't jump around when the misfire hits. Alpha tables are at around 95 on b1 & b2. I can shut off individual coils through MODIS & each one gives a very noticable change. Same with injectors. 

Going out on a limb here... I had the exact same issue. Turned out I had a faulty injector. Test resistance in the injectors... look through my profile and you'll find a post I've written up on it. I had similar issues to you... car would sound like dog balls on idle and under high load I had a small misfire that I couldn't notice without looking at afr's

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