Occasionally stumbles when coming to a stop?

[blackyote_317]

Hey everyone, I have noticed recently that my car occasionally stumbles when coming to a stop. RPMs will briefly dip below 500 before coming back up to normal idle right as I get below about 5 mph or stop completely. Well today they dipped enough that it killed the car. No problem, it fired right back up and no CELs. It's a manual and yes I'm sure when this happens that I'm in neutral or the clutch pedal is depressed. 2017 GT, VMP tune, PMAS intake.

Thoughts? I'm going to check my MAF when I get home to make sure it didn't come halfway unplugged or something.

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[Adf020]

I have a 2018 ecoboost and have the exact same thing. I cleaned the sensor and air filter and it did not help much. It is kind of worse for me when the AC is on too. If you find out what is causing this let me know because I am stumped.

 

[Mike's Mustang]

Check your vacuum lines. I had this happen before on a different car after some work was done. Turned out one of them wasn't fully seated by the shop and popped itself out. Pushed it back in and fixed it.

 

[Ebm]

Hey everyone, I have noticed recently that my car occasionally stumbles when coming to a stop. RPMs will briefly dip below 500 before coming back up to normal idle right as I get below about 5 mph or stop completely. Well today they dipped enough that it killed the car. No problem, it fired right back up and no CELs. It's a manual and yes I'm sure when this happens that I'm in neutral or the clutch pedal is depressed. 2017 GT, VMP tune, PMAS intake.

Thoughts? I'm going to check my MAF when I get home to make sure it didn't come halfway unplugged or something.

A quick fix is to ask your tuner to raise your idle rpm unless you specify that on your SCT device. Mine did the same thing. I raised my idle rpm in my SCT device and it hasn't stalled since. It isn't the correct fix per say, but it works for now.

Possible causes: maf sensor dirty or broken, throttle position sensor bad, throttle body gummed up and needs cleaning.

 

[lacanteen]

I had an Explorer do this some years back. It was the throttle body.

 

[blackyote_317]

A quick fix is to ask your tuner to raise your idle rpm unless you specify that on your SCT device. Mine did the same thing. I raised my idle rpm in my SCT device and it hasn't stalled since. It isn't the correct fix per say, but it works for now.

Possible causes: maf sensor dirty or broken, throttle position sensor bad, throttle body gummed up and needs cleaning.

Thanks to everyone for chiming in! I don't think it's a tune issue. Has been on the same tune for a long time. I do think I sorted it out last night...maybe. I forgot I did this but I had adjusted the MAF a little while back to sit a little further down in the engine bay and I think the fan kicking on was screwing with the signal. I didn't think the turbulence would affect it much since it wouldn't be in the intake tube but perhaps just the vibration from it or something. Since putting it back in the normal location and clearing memory, it seems to idle smoother and no issue when I drove it around the neighborhood. Will take it for a bit longer test drive tonight and make sure.

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