My '06 F150 has turned 6,000 miles. I had the dealership change the oil at 3,000 miles, it was a freebie. Ever since I bought this truck it has been hesitating (hick-ups) at times. I have a large hill in front of my house and it almost always would hesitate going up this hill. The hesitation feels like a gear shift without shifting. Other than the hill, it would hesitate occasionally while driving on flat surfaces, most notably when accelerating from a stop sign or light.

This weekend I changed my oil with Mobil 1 (5W20). The hesitation is gone!

The oil I took out of the crankcase was pitch black and very thick. Didn't look like oil I would expect out of a 3000 mile change. I wonder if my dealer really did change my oil at 3,000.

Any thoughts on the hesitation and why changing oil to Mobil 1 would eliminate it?

Thanks in advance for all replies.

 

Makes no sense.

 

if it was thick and very black then the oil was obviously bad. viscosity broke down and caused the engine to work harder just to keep going.

i have heard of some jiffy lube and similar places using used oil. they did "change the oil" but fresh oil wasnt put in. maybe your dealer did that.

 

Even at 6K the oil should not be black, not unless it's a diesel. Heck my Buick has gone 16K before an oil change and it wasn't black either. Make's me thing they used the wrong oil or additive ??

 

How quickly the oil turns black can just be the additive package and basestock of the individual oil. The additive or basestock itself can change color when subjected to heat. Or if the oil is better at suspending contaminents than the previous oil it will turn dark more quickly. I have seen enough analysis to know that the color of oil has nothing to do with its serviceability. I have had lubricants that were crystal clear and yet had no TBN left to fight acid at 5000 mi and I have had lubricants that had reserve capacity at 45,000 mi. The only way to tell the actual condition of an oil is with Used Oil Analysis. However even a Blotter Test is better than just looking at it.

As to the "hesitation" if it the same one I noticed in my truck when new it happened at speed in certain throttle transitions and I came to the conclusion it was caused by converter clutch going from unlocked to lock. The PCM may kill power momentarily during this lock-up under certain conditions. Evidently the PCM has a learning mode because it ceased at around the same mileage as yours.

BTW unless the contract has changed hands again the factory fill in your truck was a Shell product and the dealership oil would most likely have been a ConocoPhillips (Motorcraft) product. However some dealers use other products despite the pressure from Ford to use Motorcraft Oil.

PS Thickening of oil would be viscosity increase from Oxidation or Nitration. Thinning would be viscosity breakdown from shearing.

 

tHAt's a pretty good post right there.

 

no kidding i enjoy reading post from people who know what they are talking about and explain it, you can tell just by the wording this guy is confident in his post.

 

Makes sense.

 

On a additional note:

If the dealership changed the oil/filter it should have the aftermarket Purolator produced Motorcraft Filter or other aftemarket replacement. The OEM Filter is a different Champion produced filter. Ford does this so they can see if the filter has ever been changed when they get engine claims.

 

Thank you all for your replies! Gene K's reply helped me alleviate my worries, thanks! The filter I removed was a Motorcraft with an MS part number. I'll quit my worrying and get back to enjoying my truck.

 

The other possibility is that the PVC valve wasn't functioning correctly due to the thick oil, and the new oil unstuck it. That little hesitation, in my experience, is often due to pcv issues.

If the problem returns, of course check the computer for codes, but a pcv valve will only run a few dollars. Easy fix.