stalkn

ok so I recently imported a 98000km Evolution IV from Japan

Stock apart from:
3" cat back
aftermarket airfilter in OEM airbox
HKS Seq BOV

Car has a weird miss-fire that Actually sounds like a boost or fuel cut to me. It goes flat as a pancake and pops almost like antilag
It happens right at the transition between Vacuum and boost .

So far I have replaced the spark plugs with BPR8ES gapped to 0.6mm and new Coils.

this made no change AT ALL so after help from MR Google I replaced the Exhaust Cam Sensor.

First two test drives of about 3-5km each with new sensor and the car was PERFECT.
no miss stutter or hesitation and car made boost as one would expect all they way through rev range

Third test drive about 30 mins later and car was instantly back to the exact same problem, fine off boost (maybe a very very slight uneven Idle) but a huge issue at the transition which doesn't go away ie cant be revved through but disappears if I let engine drop back into Vacuum

What the hell is going on ??????

4G63Rules

iTrader: (10)

I had the same problem you are referring to with my IV and I replaced everything:

cam sensor
water temp sensor
crank sensor
MAF
injectors
coil packs

But what eventually fixed it for me was two bad spark plugs. After that, car ran like a top! I would try the coolant sensor and maybe clean the MAF. Check your injector clips for corrosion. Make sure your timing is good. Hope you find your issue.

stalkn

thanks for the ideas I will look into those as well

Plugs and coils are new and made no change at all but i might close the plug gap up to 0.5mm


Whats got me completely confused is how a new cam sensor fixed it momentarily!