Just changed my fuel filter on my 07 5.4L Lariat today. This will be the second time i done this. So this time i go buy the filter come home go to change it and notice that the stems on the new filter are smaller than the stems on the current filter. I go back to the parts store and find out there is a difference between filters for a Flex fuel system and a Regular Fuel System. The Flex fuel filter has the smaller stems. I look at the window sticker that was on the truck when i bought it new and it says 5.4L ethanol Flex Fuel. But this filter will not work because of the thinner stems. So i buy the other one just like the one on the truck and fits perfect. Why i didn't run into this problem last time is beyond me, i must of thought i didn't have the Flex Fuel system and got it right. So is my truck a flex fuel Engine or not? Would the Vin # tell me this.

 

Well I'll tell you this much, if you bought the truck new and it said it was flex fuel, and it turns out it isn't, you should definitely be having a talk with that dealership.(Not saying flex fuel is better, but you should get what you paid for)

 

The eighth letter in the VIN should be a "V" instead of a "5" which means it is a flex fuel engine. Hope this helps. Also on the engine decal under the hood and behind the fuel door.

 

What color is your gas cap ??? If its yellow its a Flex fuel truck.

 

Things like fuel lines don't always go with models like they say they do. I run into it a lot on all different cars at work where the fuel filter that's listed isn't on the car. It seems like they run out of fuel lines or something and instead of halting production they just stick the other type on there because it makes no difference.

 

i ran into this problem yesterday and when i went back to turn it back in another person helped me than the first time and he said there are two different production dates that different fuel filters where used. hope this helps i have the same thing that you have

 

My truck is an 07..... here is a pic from my cell

 

See where it says ethanol fuel or gasoline fuel, that means it is flex fuel.

 

I don't think I would put ethanol in that one. Mine specifically says E85 with a bright yellow gas cap, alot of gas stations use E-10 which is basically unleaded gas with ethanol in it which is possibly what that means. I would use what the vin # states.

 

I believe they put the yellow caps on the truck in 2008. My 07 has the black fuel cap, as pictured in my last post, but is E85....It all depends on what the OP has in his VIN.