R34 Stutter At Idle

[TJZ]

My r34 gt has a stutter at idle and seems to be down on power (even for a non turbo). It's always had this issue. A few months ago my coil packs died and I replaced them with yellow jackets and changed the plugs while I was there. I thought the issue might have been the coilpacks dying but after changing them the stutter is still there. I've done a search on here but can't seem to find anything. Please help

[TJZ]

Also I've check for fault codes and got 55 (no faults)

[HKS034]

Do a minor service and make sure you are using a good oil for the RB25de, check compression in all cylinders aswell.

[TJZ]

Serviced in back in February. Changed oil with penrite hpr5 5w-40 and changed air filter and fuel filter at the same time