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overfueling causing a rich misfire due to air leak, dodgy afm, bad spark (coils or spark plugs).

That or it is leaning out due to fuel pump.

Smoke test the intake to rule out air leaks, replace the coil packs as good maintenance on a 20 year old car, new plugs with 0.6mm gap to confirm it isn't a spark issue. Change the fuel pump as good maintenance on an unknown 20 year old car.

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Does the car run like absolute shit at all revs? If it is out by 2 teeth it would be terrible to drive!

I hope that is what is the problem, I just think if that was the case that whoever did the belt would have noticed straight away.

i bought the car like that, and the previous owner just changed it in the service, problem is whoever done it didnt know what they were doing as they were a genral mechanic, not a nissan mechanic specifically...it has to be that. its getting put on the dyno tomorrow, air/fuel ratios and boost are being checked and they will find out whats going on

Must have been a pretty shit mechanic if they can't line the white mark up lol. Nothing nissan specific about doing a timing belt.

Good call with taking it to a workshop, be easier than trying to guess what is wrong with it.

Edited by Rolls

yeah well these guys do skylines day in day out so they know whats going on, and he said garunteed they will find the cause and the computer can be read by them obviously so enough stuffing around with it ill get it looked at properly haha

Took it to Toshi today and he figured it out....

He said the way the stock fuel pump works, it gets a lower voltage when at idle and low revs and then the full 12v at high revs.

The Walbro apparently didn't like this so he wired in another ground so that it gets full power all the time.

Problem seems to be gone....lets hope it stays that way.

^^ good job mate. my problem is fixed too. coil pack #6 was missfiring. and the ecu wasnt grounding properly apparently. got a blitz dump pipe fitted aswell while it was there. made 145rwkw in 3rd. not bad for a stockie

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