Originally Posted By: ChrisD46
So your saying the 'ol Italian tune up will take care of DI intake deposits ? ... Something like 20 minutes over 3K RPM ?
I would argue that high RPMs alone is not enough (it might be, but I need to see some actual data). To be sure you need to put your foot into it to get the temps up. Simply running at a higher RPM with a barely opened throttle might not do that.
In other words, mix a track day into your regularly scheduled maintenance. What I've been doing, every 10,000 miles or so, is going to my favorite, desolate backroads and running flat out for extended periods of time. 81k miles later my car is showing no signs of power or efficiency loss. One day I may pull the manifold and clean it out anyway, but so far it doesn't seem to need it.
Alternatively I've seen a lot of DIYs on soaking the valves in various chemicals. Given that the intake manifold has to come off the difficulty level varies depending on the model of car. Thankfully it's not so bad for the 2.0 equipped VW/Audis.