Thanks Grey Ghost and Bootleg,

Yes we are dealing with the ethanol problem as well. (I think that there is legislation that limits to 10%.. though I might be wrong.) I have been running all E10% fuel since new... but Chevron offers 0% Ethanol in the Supreme Plus 94 octane. Tried that for one VERY EXPENSIVE tank... NO difference.

The Cat and the O2 thoughts are the ones that provoke my brain to think about these possibilities the most. I wonder if I am a victim of a frog slowly being cooked in a pot? You know the idea that if you put a frog in a hot pot of water they will just jump out... BUT if you raise the temp slowly they stay in because they can't feel the change. Not having driven another SR5 since this all started, I have no "baseline" to compare it to. My other car is really quite fast so the 4runner has always felt very slow to me... but speed is not the 4runners forte.... so it never bothered me. I wonder if the performance has suffered as the milage has changed???

Great thoughts! And ones that I will share with the dealer. I think I will test drive another SR5 while they are looking into the Cat and the intake / O2 A/F mixture.

Thank you! -to all the members for their help on this. Great forum! (It's going to cost me some money though.... as I look at the pics of your rigs with nice mods I feel a hole burning in my pocket!)