Rb20 Engine Problems

[daskyzigts4]

ive got a 1990 r32 gts4 skyline,slight problem....when car reaches normal engine temp,engines becomes more lumpy sounding like a v8 or subaru.still makes boost,but with lack of power like its being restricted.just had manifold machined didnt fix it.alternator was stuffed,thought it might of been de-tuning itself due to lack of volts.any ideas??thanks

[blind_elk]

With age, the ignitors are prone to break down when they get hot. If it runs rough at idle, do the standard "which coil is misfiring" test. Try a cool wet rag on the ignitor module, see if that fixes the misfire.