Hey all.
My car (R32gtst) has been blowing some sort of carbon out of the exhaust for a while, i think its oil (when its under boost). After a base map tune, fuel pump and boost controller i am starting to wonder whether it might be the piston rings go?
Also, since installing the fuel pump (bosch 040) and boost controller the revs appear to be surging during idle. Between about 500 and 1200rpm. any ideas what this could be?
Fuel reg is stock.
Any advice or help would be much appreciated.
Thanks