Car almost stalling when decelerating

[MjDubai]

Car is in operating temps, AC is on, and its reasonable hot outside.. while driving car feels normal, but the moment i decelerate and come to a stop rpm would go below 500 and jerks then go back to normal. It only stalled once, i cleaned the throttle body and MAF sensor, but it still does that. When I shift from N to R or D, it does the same thing, it goes below 500rpm as if the car will stall but it just goes up suddenly then to 750rpm. All this happens when car is in operating temps, and AC is on, and I can hear the cooling fan on high speed.
I was told that it might be Throttle Position Sensor, but not sure.. Any had the same issue before or knows how to fix this.

 

[Macman45]

Vehicle speed sensor maybe, is your speedo outputting correctly?

 

[MjDubai]

yeh, all gauges seem to be working correctly..

 

[Midlife Crises]

Vacuum leak.

 

[MjDubai]

if its a vacuum leak, shouldnt the CEL come on and give a lean afr code reading?

 

[Macman45]

Does it do it at idle just sitting there? And not necessarily, also check your air intake after the MAF sensor and around the throttle body

 

[MjDubai]

only when its on D or R.. nothing when idling on N... when coming to a stop its jerks below 500rpm then go back up.. and when putting it in D or R from N.. i noticed something also, when changing from D to N, rpm goes to 1000rpm, stays there for a bit then goes back to 750.

 

[MjDubai]

and by the way i have a JLT series 3 CAI, tuned using an sct x4 tuner with 93 octane

 

[JeremyH]

Did it just start it or has it been doing it. Also check and clean the cmc valves. How many miles on trans fluid?

 

[Nuke]

I'd clean the TB 1 more time and, if it persists, then run a can of Seafoam thru the tank. If it STILL persists, than I'm on board with the vacuum leak, or possibly air in-leakage ahead of the TB.

 

[Kohaku]

Did you remove the throttle body to clean it?

 

[Juice]

and by the way i have a JLT series 3 CAI, tuned using an sct x4 tuner with 93 octane

How long has the tune been installed? Anyway you can look at what the fuel trims are at?

 

[Dino Dino Bambino]

Here's what you need to do:

1. Disconnect the negative battery lead.
2. Remove CAI, remove TB, and thoroughly clean TB inside and out.
3. Clean the MAF sensor.
4. Reinstall everything making sure the connections between CAI pipe and TB, and between the air filter & CAI pipe, are correct and air tight.
5. Reconnect negative battery lead.
6. Start engine and go through idle relearn procedure.

Hopefully this will solve your problem.