Mostly due to the V8.
I realized long ago that if a car had engine options, the smaller ones were often better choices long-term than the larger ones.
I am on my 3rd 4-cylinger Camry and they are bulletproof.
I don't generally agree, but with the compact and sub compact cars, yes. But for mid to full size cars and small trucks (Ranger, S-10, Sonoma, Dakota), V6 is my preference. I have personally drove two 3.8L GM V6s to over 200k miles. My dad has had 3 over 200, and one was very close to 300k before the transmission let go. The 4.3 V6 in my moms S-10 was an amazing motor until she rolled the truck on ice. GM's 3.8 is actually now their best selling engine of all time.
Now with full size trucks, there is no reason to get a V6, unless it is a diesel. To my knowledge, Dodge is the only one doing that right now for domestic. For imports, I couldn't tell you, I have zero interest in buying one. Chevrolet is now offering a 2.8L I4 diesel in the Colorado now. Rated at 369 lb-ft of torque with a 7,700 towing capacity and being able to pull 31 mpg on the highway.
Now for my explanation on the relationship between octane and fuel mileage. There is a very common myth that the higher the octane the more power you car will make. This is partially true depending greatly on the engine and its electronics. A higher octane fuel, technically has the exact same amount of energy at burn than lower. They have the exact same potential energy. What the octane rating actually translates to, is the difficulty of igniting it. The higher the octane rating, the more difficult it is to ignite.
The electronics I am referring to that make the difference is, the engine having a "knock sensor" and having the ability to adjust ignition timing on the fly to prevent knocking. For those that don't know what knocking is, here is a brief explanation. Knocking occurs when the air fuel mixture in the combustion chamber ignites before the spark plug fires. The non planned ignition source is usually toward the piston side of the combustion chamber. When the spark plug fires, it doesn't have as much air fuel mixture to ignite, and when the two flame fronts meet, it produces the knock sound. This slightly reduces power, but what really steals the show with power loss, is when you engine automatically retards the ignition timing to ignite the mixture before it detonates. This is much more of a problem with higher performing engines, as compression ratio has a direct relationship to knocking or detonation as most auto techs and car guys call it. But with a higher compression ratio, you can make more power, but when you are only using a third of the power possible, the engine will generally operate more efficiently. The problem with going to the higher compression ratio is the higher chance or detonation, this is the primary reason any auto owners manual specifies 91 octane or better.
Some cars, have the ability to advance timing a bit when higher octane fuel is used. This is what adds to the power and fuel efficiency. It does not come directly from the fuel itself. This is why some people say higher octane doesn't affect cars, it used to make no difference, aside from the knocking issue on higher compression engines.
Now, the US, and Europe use two different methods for displaying the octane rating. I can't explain it, but there is a great video on youtube.
