hey all ive just bought a vl turbo it is a genuine a8 and am having problems with it missing on boost. have replaced the spark plugs,leads,oxy sensor which was stuffed anyway but the problem is still there. then i replaced the fuel filter and it ran better but still had a slight hesitation everynow and then. i checked timing and advanced it to about 25 on the marks and now it seems 2 run sweet. and the air/fuel gauge runs where it is supposed to. would appreciate any help cause i know something is wrong. it is a stock a8 with a highflow, cooler and exhaust. cheers

Quote: Originally Posted by t3calais [View Post] hey all ive just bought a vl turbo it is a genuine a8 and am having problems with it missing on boost. have replaced the spark plugs,leads,oxy sensor which was stuffed anyway but the problem is still there. then i replaced the fuel filter and it ran better but still had a slight hesitation everynow and then. i checked timing and advanced it to about 25 on the marks and now it seems 2 run sweet. and the air/fuel gauge runs where it is supposed to. would appreciate any help cause i know something is wrong. it is a stock a8 with a highflow, cooler and exhaust. cheers Well, it could be a whole range of things ,like lately my VY SS Commodore has this habit of developing a misfire in heavy traffic, I found 2 possible causes of this problem :- 1 - I was getting grass clippings stuck in my fuel pump when buying the fuel at the Caltex Woolworths , I was running the 98 Vortex fuel , now I run Shell V power. 2- I figured I better give the plugs a clean to possibly eliminate the problem , they have done 60,000 kms , Holden recommends changing them at 80,000 kms for the LS1. Both of these things seemed to temporarily fix the problem, I have ordered some new spark plugs for it (genuine) as I think I have narrowed the problem down to that because the engine picked up heaps more power after doing that , but I think at least 1 plug is still faulty. I had an issue with detonation on the way home from work from the central coast as I was going through Warnervale and I was hoping it wasn't a clutch or transmission problem, so I am sure there is a problem with the ignition system , the plugs don't seem to be getting the right voltage at the electrodes under heavy load. As for the VL's ,well I can name 3 other things :- Air leaks in the intake , faulty TPS and faulty AFM.

thanks mate. i closed the plug gaps down and it seemed 2 fix the problem. appreciate it though