I'm not entirely sure what the VANOS solenoid valves do exactly...but I replaced all 4 on my 4.8is N62 as part of some recent upgrades (also did new NGK Iridium IX plugs, ignition coils and serpentine belt earlier in the day).
To my surprise the new VANOS solenoids had an awesome improvement to my engine responsiveness. Best way to describe it is that it's SOOO much more smooth now.
Previously I had a lag or delay after giving it gas (either light or WOT). After applying throttle it would just think about it for a second but then suddenly kick it and jerk your head. Now it's accelerating evenly and more quickly like I always expected it to. Seems more "peppy" on the butt dyno.
Am I going crazy?
