Hey everyone my names Jeremy (obviously) and I don't post often because of my work schedule. I was looking into suggestions for a persistent problem. I've been getting a stalling issue every so often after coming to a stop and trying to accelerate. Once it stalls its followed by a flashing check engine light and no start until I cycle the ignition. When it happens there is a relay that clicks in the fuse box under the hood. I was looking at the ignition timing in park and it stays around 6 -7 degrees but when put in drive jumps to 20 - 22 degrees. Is this normal on the timing? No check engine light while driving and no powertrain codes. Thanks everybody for any suggestions!!!!

 

I figured I'd compare reactions in different vehicles. Our 2003 Mustang 3.8 responded similarly with timing when going from park to drive. I'm guessing this has to do with load increasing when the transmission is put into drive. Does anyone know stock idle speed for the 2.5 in park? Our is idling around 900 - 930. I was messing around with it for a bit and if I remember right reducing the idle (idle air bypass set to roughly 30%) and timing (set to around 10 degrees) in park seemed to make it a little smoother but that was yesterday and would need to go over the settings again to confirm.

 

It is normal for spark timing to change when an automatic is not in Park or Neutral.

Yes, it is for the load on the engine when in gear.

Not sure what spec. is on warm engine 4cyl idle, above 900 seems high to me.
The 4cyls are higher RPM motors so have low torque under 800rpm, a 650rpm idle, like a V engine, would cause starting off issues, but 800-850 seems more reasonable in Park/Neutral, then maybe a bump up when in gear, +25-50rpm


Stalling out could be a couple of things.
Could be time to clean the IAC Valve, they can get sticking and not respond to computer instantly.
Turning key off and on opens IAC valve all the way so would unstick it.

Or could be TCC(torque converter control) solenoid is not responding to computer control.
TCC locks and unlocks the torque converter.
When coming to a stop it is unlocked so engine can idle, then when moving again it will lock which gives better MPG and power than the old, always unlocked, torque converters.
When coming to a stop if you see RPMs dropping more than normal and a bit of a lurch then TCC could be the problem, it is staying locked too long

 

I cleaned the IAC just a few months ago when it started this behavior. I'm using ForScan to communicate with the ecu and sensors. In ForScan I can adjust the IAC from 0-100%. The IAC response time is good, so I don't believe its sticking. I also have unplugged it while the motor is running and it responds by killing the motor. You have my attention with the TCC. Great suggestion! I think ForScan lets me cycle it on and off. I'll check on my next day off. Will I be able to hear the TCC solenoid cycling on and off? Thank you for the help RonD. I'll let you know what I find.