Anyone else have this issue???

When I an driving around the city and say I am going 30mph and I am rolling up to a stop sign w/o hitting the break the truck will feel like I hit the breaks at 25mph. This happens all the time, not sure if it the truck shifting gears or what???? It not a huge feel, but it is like I just tap the breaks, but really I am just rolling to the stop sign.

Any ideas???? I have an ’06 F150 SCAB 5.4L

THANKS

 

Anyone???

 

Pay attention to your Tach when it happens... Do you notice that your RPMs increase? If so, it's probably just your tranny downshifting into 1st. Another possibility is that it's just your a/c cycling on/off at that particular time (however it's very unlikely to be this if it happens at the same time during each stop)... As a last thought, my wife had a 2004 Honda Accord that did this exact thing. It turned out to be a faulty brake booster. Somehow the booster exerted extra "boost" after keeping on the brake pedal for a few seconds. The result was that the car would have a little jolt each time we would attempt to stop...

But my gut feeling is that you're just noticing the downshift.

 

I've noticed this on my truck, too. It's just downshifting--perfectly normal.

 

ya, the RPSs are normal....i guess it is just the down shifting....didnt notice it on my '04 F150

 

I was searching the TSB's for your issue... While one doesn't exist specifically for the 2-1 dowhsift, there is a TSB for a harsh 3-2 downshift. The solution is a PCM calibration... You may want to take it into your dealer and see if they will do a PCM update to see if it cures/minimizes your situation. Often times, PCM updates have a significant effect on how the tranny acts (sometimes good, sometimes bad).

 

could this effect MPG? Seems like it has been going down over the last 2 months
Thanks so much for your help!!

 

Downshifting into first at 25mph... That would be a FIRM shift.

You may be noticing a 3rd gear locked tc to a 2nd gear open tc. Remember the tranny is electronically controled so it can slip the TC as much as it wants (upto 1000pms per the pcm) so you may end up with the SAME rpms when it occurs but more engine braking.

 

MPG has gone down the past two months because of winter gas here in MN. Same thing happens to me. I lose about 1-2 MPG in the winter and about 3 MPG in late Jan and Feb.

It has to do with the blend of gasoline that MN requires in the winter months.

It'll go back up in the spring. It stinks, but thats what is causing the lower MPG.

Duke

 

thanks for all the help...4got about the different gas blend..we have that issue here in michgan too.

Well....i guess this issue that i am having is normal.....correct?

 

Correct

Duke

 

A suggestion for the gas blend..............Try a power reset of the pcm.This will put the unit into the adaptive learning mode,forcing the pcm to "relearn" your driving habits.
Just my $.02 worth.