Rb25De S2 Bogging Down

[Jordy32]

Hi guys

A few details before we start

R32 Skyline Coupe
RB25DE S2 (Manual) - ~160,xxxkm

RB25 Pink Label AFM
RB25DE S2 Manual ECU
BP 98 octane fuel

Basically what's happening is my revs bog down at around the 2.5k - 3.5k mark at around 1/4 - 1/3 Throttle and it sounds like it's surging almost? I had a similar problem recently throughout the whole rev range unless I had the throttle wide open so I ordered a new TPS and after installing and adjusting it that issue was solved however I'm still getting this strange bog down

So far I've replaced the Spark plugs, checked the coil pack loom for any wear but it looks quite clean and in good condition. I've recently replaced and adjusted the TPS, I've cleaned the MAF a few times now, replaced all the fluids, filters, air filter etc etc

I have coming from Nissan a new O2 sensor and fuel filter as i though these might be playing a part in the matter, I've also gone over the engine grounds to make sure nothing is going wrong. Should i be looking at a set of coilpacks? they look old/stock so they might've had it, im pretty baffled to be honest

My thoughts are that either the coilpacks are dying, or that it's running too rich (stinks of fuel lol, no idea of the o2 sensor history) and simply can't burn it all until i open the throttle more, I'll try find another AFM and see if that helps at alll

If anyone has some ideas to what I could try, please let me know Thanks!

[Mick]

start with a cheap bottle of injector cleaner, mine was having similar problems where it will surge sometimes unless the foot is flat and i tried so many things and a cheap $10 bottle of injector cleaner fixed it within 20mins of driving

[Mick]

it may not fix it but for the sake of $10 to try it is worth it and giving your injectors a clean will be a benefit anyways

[Jordy32]

Thanks Mick, i put a bottle in, unfortunately i don't drive the car that much so it might take a week or two to get the whole tank and bottle of cleaner through the injectors but we'll see how it goes

[IM-32-FK]

Whenever mine bogs it's usually because I get coolant in the spark plug chambers. Removing the spark plug will drain the coolant into block and fix the problem

[Jordy32]

That doesn't sound normal at all

I replaced the spark plugs quite recently and it was as dry as a bone, ill check again

[Mick]

how did it go?

[Jordy32]

how did it go?

Hey Mick

Filled the car up and put in a bottle of cleaner and went for a drive, definitely felt a little better about halfway through the tank, still a bit surge-y and splutter-y at times unfortunately but a little better, car feels nice when it's smooth!

My O2 sensor arrived which i put in last night but I'm yet to take it for a drive so we'll see how it goes

[Jordy32]

After changing the O2 sensor, fuel filter and a bottle of injector cleaner, the car seems to run noticeably smoother and cleaner

Thanks for the help