While braking the idle is rough. it feels like if shaking . like if is going.to stall .
However when the truck is at a stop the idle is very smooth .

 

Clean the throttle body and particularly the idle air control.

Tim

 

I did clean the Tb with some carburetor cleaner .
for sure is some kind of dirt still . I I guess next step is to do a deep .
not sure why is only rough around 10 mph
once is stopped the idle is very smooth

 

usually the IAC is the culprit but sometimes cleaning will not fix it. Cause is that the IAC is not reacting fast enough to let air in to increase idle RPM. Normally the base idle screw which holds in position the throttle plate is not adjusted but sometimes the base idle hex screw gets beaten down thus lowering the plate to choke off the engine RPM. But that is an adjustment of last resort. If it were me I would replace the IAC if its original.

 

@dionkraft

I cleaned the TB and even though it gets a little better the problem.is still there. I was looking to.replace the IAC but cant find it online
is the oem part available .

btw the idle is only rough when coming down to
after a full stop is very smooth

 

Try this test...put into Neutral and then come to a stop. What happened?
Did the idle stay normal or did it also start to stumble?

 

I'm not sure the IAC is adjustable, it is not on my 2005 anyway. I have also been told to never use carb cleaner on a throttle body, unsure why.

I would look next at the the throttle position switch, which on my truck is located on the top of the intake, under the engine cover, all the way in the back.
Tim

 

I did the test and found while in neutral the Rpm act fairly normal
I took a video to check how was the rpm acting .
Problem start
around 10mph (rpm climb to 700) getting worse at 5mph
the Rpm goes higher (850rpm) for 3-4 seconds
Then at full.stop it goes back to 580 and stays smooth

If truck is in neutral the Rpm stays at 600ish till stopped then goes to 580 and stays smooth

Tim . thank you for the suggestion. I had an issue qith the TPS a few months ago . was a temporary thing which didn't need any fix but the truck goes into safe mode (locking rpm at 1500) and throwing a code for the tps .
after turn off the truck for a few min all came back to normal

 

The only way to find out if your TPS is within the program limits is to use a scanner to see what the percentage of WOT (wide open throttle) is and to make sure it does not break thru those limits. Basically you would have to drive the truck and then let go of the throttle to see it does not go below 0%. Another method is to disconnect your IAC motor at idle so that when you go off idle it will go back to the orifice opening to have the same idle it has before. If you experience the same problem it is not the IAC's fault. I am beginning to think that the fuel is shut off to very lean when you let off the throttle causing the stumble...but thats a guess at this point.

 

It sounds like its downshifting. That's what my 03 does when coming to a stop