Gtr Surge...

[donkey]

well here we go.....nissan gtr r33 power fc. problem is when driving car holding a constant speed, car starts surging, then the backfiring (changing gear first and second) puff black smoke, black carbon deposits over back of car.....obviously running rich, because fouling plugs. i live in queenstown (nz) so air pretty thin up here in summer, car runs sweet in winter (colder air, more denser) but when summer hits problem starts, car was dunno tuned in auckland (sea level), had a wrx, link computer that was also dyno in auckland then brought down here, same problem, dont really want to lean out mixture.......any ideas on my theory???.....cheers

Edited January 21, 2008 by donkey

[blind_elk]

Theory seems sound.

Only solution would be to go right through all the fuel maps and take a bit of fuel out.