Ok so here is a quick before and after story...I used to actually get the estimated 28 mpg hwy, at one point I remember taking a 4 hour trip from Los Angeles to Las Vegas with full A/C blasting and steady driving with cruise control engaged at 85 mph. Can anyone guess my MPG for that trip?? A whopping 34mpg! Currently I'm seeing a combined 22 mpg city/hwy and I'm at a lost to what happened to my beautiful mpg's. I've asked my father who is very knowledgeable about cars and he says that day to day driving causes carbon build up in my engine which drastically reduced my fuel economy and engine efficiency. He suggests that I drive it for an extended period like on another trip to Vegas to burn off the carbon and my mpg should improve. Has anyone had any similar experience with their MPG decreasing?

 

This happens to direct injected engines. There is a lot of forum voodoo out there on this subject... quick fixes, preventative maintenance, oil service intervals, oil, etc. One thing is for sure, you can have a spark plug removed for a pro to put a scope in on your valves. If they are caked in carbon, then its time to have it cleaned. The dealer knows how to do this service, (I know for sure that VW knows, lol) but you might be able to find an independent that could do it as well.

Nice thing about this service is that it restores a bit of power as well! Good luck man!

 

attempt seafoam.
ive noticed difference in my vehicles and some of my friends

http://youtu.be/2hrasAYG42g

 

350?430?460? Make's me worried because I have accepted that I get around 24 mixed in my 430.

 

Gs300...not sure why my car info doesn't display. will not be seafoaming, I will just drive to Vegas again next month for labor day. I will post results!

 

If you had enough carbon buildup the car would be shuddering/shaking and feel like it's misfiring particularly when letting off the gas and coming to a stop or idling. Mine was doing this, Lexus did the top engine clean under warranty.

I'm going to guess that you waited too long to complain about this for the warranty to apply. I'm pretty sure Lexus would end up charging multiple hours of labor to do this even though most of the time is "waiting" time for them but it does involve removing plugs and the valve cover, a few new gaskets (due to removal) and a bottle of the... cough cough.. GM... top engine clean chemical.

The good news is that the car seems to be able to go a good 60,000+ miles between needing to do this so even if you do have to pay a few hundred bucks for it it's worth it. If somebody with TIS access could find the procedure for that particular TSB and post it/send it to us I don't see why you wouldn't be able to attempt it yourself or bring it to a shop with a cheaper hourly rate that also won't charge for the time that they are just sitting there while the valves marinate.