Help, Stall Issue When Clutch Depressed

[HFBPA889]

Any suggestions would be appreciated. While driving the car and on deceleration while depressing the clutch the RPM's will drop low enough to create a stall. It has happened probably 2-3 times and this issue started recently. The wierd thing is it's 90 deg today and with the A/C on it's worse, RPM's will drop to zero clutch depressed on decel. I am going to clean the MAF (HPX) and clean IAC. I had the car tuned in May 2013 and was not initially a problem. Could it be the tune? My relevant mods are as follows.

Hellion single blow through conversion
Egr, FRPS & pcv delete
80# Injectors
Lethal Return fuel system w/Div X rails
HPX MAF
No cats and most rear down stream O2 sensors deleted

Also vacuum at idle is 21-22 but with A/C turned on vac is at 18-19(not sure why).

 

[fbody83]

There are settings in the tune to adjust this however since it wasn't a problem when you first got tuned then I would say there is something else going on. If you're just idling with the clutch out and then rev the engine, does it want to stall when the RPM's come back down? Do you know how to datalog? If so I would datalog your volts to see if you have a low voltage/alternator issue.

 

[HFBPA889]

There are settings in the tune to adjust this however since it wasn't a problem when you first got tuned then I would say there is something else going on. If you're just idling with the clutch out and then rev the engine, does it want to stall when the RPM's come back down? Do you know how to datalog? If so I would datalog your volts to see if you have a low voltage/alternator issue.

I have no way to datalog, but if I rev the engine in neutral RPM's do not drop below idle(800 rpm). I do notice when my engine fan kicks on the RPM's will drop from 800 to 650 then back to 800.

 

[evers86]

You have to have your tuner add more air into the mixture on deceleration. I had this same exact problem for a while.

 

[HFBPA889]

Thanks for the response, I figured an adjustment to my IAC, and dashpot settings will do the trick.