R34 rb25de rich and no power

[rycoozer33]

So I have an r34 rb25de neo as a run around car and it has had a small missfire for a few years but not causing any problems.

I have replaced the coil packs and plugs which seemed to fix this and over time it has started running really rough and rich (stinks of fuel) when it is cold and lacks a lot of power to the point where I struggle to do 50km per hr but seems to come ok after about 20 mins of driving. 

I have since re earthed the lead going to the coil packs and replaced the o2 sensor and coolent temp sensor. I have unplugged the afm when running and it changes the running and almost stalls when plugged back in so I assume that is working.

Thoughts?

[KiwiRS4T]

Check the contacts on the AFM plug and clean the AFM element. If that doesn't fix it try to borrow a known good AFM to try.

[Murray_Calavera]

Add a turbo to make use of all the extra fuel

[MoMnDadGTR]

try changing the coilpack harness and look for broken or melted wires in harness. you can solve a lot of issues with a volt meter and doing a vac leak test by pressuring up the system. mine was a broken clip on my coilpack making a weak connection. problem was inconsistent. I also noticed my car ran way better when I set the tps and cleaned my AAC. do the cheap stuff first.