SCT Tuned... Rolling to stop, clunk to 1st downshift?

This guy did a nice right up on Fuel Trims, check it out.

Fuel Trims Explained: Short Term & Long Term - F150online Forums

Cool thanks

I'd like to add that our trucks, the 6.2L at least, use air fuel ratio sensors, which do not switch like oxygen sensors, oxygen sensors and air fuel ratio sensors are the only input for correcting the fuel mixture, the switching is the fuel ratio going lean and rich, usually 16.0:1 to 11.0:1 or 12.0:1, oxygen sensors cannot determine exactly what the ratio is, so it adds and removes fuel to try to average a 14.7:1 mixture, and short term fuel trim will switch opposite of the oxygen sensors, air fuel ratio sensors can detect within 0.2-0.3 the true mixture of air to fuel, and therefore do not require the same intensity of switching associated with oxygen sensors, so short term should not be switching large amounts at a constant throttle, but if you play with the throttle pedal while watching the short term fuel trim, it will seem like it is going crazy, but it's just the fuel trim trying to compensate for the changing amounts of throttle you're giving the engine

and I'm pretty sure the shifting from 3rd to 1st is normal, my truck always did it when I used drive, and it will do it in manual if you let it downshift on it's own, trying to get the thread back on track a little

Hey i have a question. Installing a SCT flash on my truck. Will improve my MPG for better? Or will spend more fuel.
Is because they say at
The webpage more power less fuel.

---------- Post added at 12:57 PM ---------- Previous post was at 12:53 PM ----------

It is normal they makes to shift firm. When i used to have my svt lightning with a BTS tranny I got my tune to shift firm and i like it.
Is only because the valve body. It is matter if time you get used to either the truck.

RGVRaptor said:

Just noticed this today... This is only the second day I've driven my truck with the new SCT 93 octane performance tune from 5 star tuning and I noticed when on the brake rolling to a stop that the truck shifts down to 1st gear and I'm not sure if it's 3rd to 1st or 2nd to 1st, but it sometimes is rough and I hear a "clunk" as it goes in to 1st gear.

Anyone else experience this? Is it something to worry about? Fix?

Thanks!

Click to expand...

I've been having this issue on mine. SCT 91 octane tune. When I stop fast it holds 3rd then slams first still sitting still settles on second the second I launch it goes down to first and revs completely out and loses the gear completely. Very very annoyed.

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Edit: I've done a few reflashes ranging from eco to sport to even stock Ford tune and it still does it

Similar symptoms to this recall http://www.fordraptorforum.com/showthread.php?t=48101