I'm wondering if anyone else is having any steady state cruise problems between 40 and 50 mph. It seems that since the weather is warming up our 05 is experiencing a type of surging between 40 and 50. When it's freezing ass cold, below 30, it runs fine but above 30 is when it begins. I already use premium and not from the same station. Any help would be appreciated.

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A Ranger owner's worse nightmare

problem #1 premium fuel...run regular..you are doing your truck no favors by running high test

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2021 F150 5.0 Screw

Past:18 F150 2.7, 16 F150 5.0, 14 F150 5.0, 07 F150 5.4, 03 Ranger 4.0

Master Certified Ford Parts / Warranty Admin

the tune up in it requires premium fuel so there's not a lot of wiggle room.

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A Ranger owner's worse nightmare

you're just pissing money away

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2021 F150 5.0 Screw

Past:18 F150 2.7, 16 F150 5.0, 14 F150 5.0, 07 F150 5.4, 03 Ranger 4.0

Master Certified Ford Parts / Warranty Admin

I don't know about that. I picked up 3 mpg and power on top of that so I don't feel I (pissed away money ).

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A Ranger owner's worse nightmare

using higher octane fuels in a low octane engine leads to carbon build up and pinging as well as possible head failer and over heating. higher octane fuel burns slower so it can be compressed more in high compression engines. unless youre advancing the hell out of your timing i cant imagine why you would want to waste time and money running higher octane fuels.

I don't know that any of this is true. Octane is purely the tendency of a fuel to reduce engine knock. But having said that, I would have doubts that higher octane fuel leads to up to 3mpg gain. I could run higher octane in my Mustang, and I did gain some mpg's. It about equaled out the higher cost of the gas. Miles per dollar was pretty much a constant.

Sorry guys, I'm just stating what I have achieved with the high octane tune up. My original question was only if anyone experienced rougher running engine with the winter blend of fuel.

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A Ranger owner's worse nightmare

No noticeable rough idle for me.

The surging issue you're describing isn't an uncommon issue for some SOHC engines, mine included. Their are a couple of threads on it already, some theories, no cure. A non-motorcraft air filter seems to make it worse, especially when it's snowing or rain right at the freezing mark.

http://www.fordrangerforum.com/4-0-s...any-ideas.html

http://www.fordrangerforum.com/4-0-s...hard-slap.html

08 Ranger Cold Drive Hesitation

http://www.fordrangerforum.com/4-0-s...ed-cruise.html

http://www.fordrangerforum.com/4-0-s...n-snowing.html

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2010 Ranger XL 2.3L 5 Spd 3.73:1 Bone Stock
2013 Scion FR-S 2.0L/H-4, 6spd, 4.11:1 Fast Enough Stock