Newbie here,
I'll try to describe problem as best I can. Here goes..........123,000 miles now but has been doing this since 50,000 miles. Dealer has not been able to find the problem and no codes are showing up. Occasionally (about 1 in 20 to 30 times) after prolonged high-speed highway driving (at least 4 or more miles), then coming to a stop for a stoplight or whatever, as I begin to accelerate, it kind up gives a few subdued back-fires (thru tailpipe - not intake), puffs blue smoke out tailpipe, and then chugs for about 20 seconds or so till it "clears out" and then starts running just fine. It only does this after prolonged running at 60 mph or above. Also, as its idling at the light it gives no hint that it is about to severely embarrass me by turning the intersection blue as I leave it. Perhaps this is related - I don't know. It 1st started doing this shortly after I filled up ONCE with E-85. (I'll never put that stuff in ever again). It burned that tank of E-85 adequately (except of course the poor performance and even poorer mpg was annoying), If I recollect correctly, it was the next tank of REAL gas that it did it once (the blue smoke - chugging routine) but like it was on steroids. I passed it off as the engine just adjusting itself back to 87 octane. Well, thats about it. Any ideas out there?