RPM dropping when coming to a stop, but only when warmed up

[lolford]

I have a 2015, and it's at about 105K miles, for the last 4+ years my RPM's will dip below 400 when coming to a stop. I've changed the trans fluid at 60k as well as 100k.

The weird things is sometimes the dip happens 2 seconds after coming to a full stop, so wondering could a lockup solenoid even cause that?

I've taken it to a ford dealer as well as my mechanic and both aren't sure what it would be. The other weird part is this only happens after the car is fully warmed up, if I'm just driving around town for 20 mins it won't happen at all, once it's warmed up it happens at almost every stop.

Full stop is at around 80 seconds on the chart

https://imgur.com/8M26kFU

 

[SHOdded]

intermittent drop or a drop that lasts?

usually power consumption > power production. this could be due to accessories ... belts pulleys clutches etc. could also be poor airflow measurement ... throttle body, map sensors, etc. climate control cycling will cause these also, but usually not for prolonged periods.

if you want to really get into it, check plug condition, turbo piping condition etc. check for oil pooling in the intake, intercooler, etc. see if a hose is loose, esp on top of the manifold where there are no clamps.

these computer controlled engines are not invincible but pretty precise.

 

[lolford]

intermittent drop or a drop that lasts?

usually power consumption > power production. this could be due to accessories ... belts pulleys clutches etc. could also be poor airflow measurement ... throttle body, map sensors, etc. climate control cycling will cause these also, but usually not for prolonged periods.

if you want to really get into it, check plug condition, turbo piping condition etc. check for oil pooling in the intake, intercooler, etc. see if a hose is loose, esp on top of the manifold where there are no clamps.

these computer controlled engines are not invincible but pretty precise.

Thank you for taking the time to explain!

It’s only for about a second after coming to a full stop, after visiting the dealer and my mechanic I tried a local transmission shop, they immidiately said it’s the torque converter and I could wait till the whole trans goes out or just replace the converter.

They didn’t bring up putting in a used trans but I asked just to get an idea on pricing. I’ll update back in a week or two!

 

[Texas Marauder]

Try a tube of Shudder fix. It is not made specifically for your problem but, it is cheap enough to try.

https://www.amazon.com/Lubegard-19610-Tranny-Instant-Shudder/dp/B0002JMLQU

 

[luigisho]

Motorcraft released their own friction modifier for tq conv shudder. Price per volume about the same

https://www.amazon.com/Ford-XL-3-Friction-Modifier-Additive/dp/B000NU5LP6?crid=2R1AVK0OOTOZT&dib=eyJ2IjoiMSJ9.XRg4Jj2BblT5ybrlcMhPzYYphMPnyy7eqELykkHrMhZcCky0L_0ZmWKyRIEnM0p_1Kjs2ymuZ2YTTzmZdtii9MDGVDvorn6vgK8k2CI13HK9VOMMJVlsEnCNFfa4S9Tj4jBEI-g7r2Lmr7wF_d_bhGWe6M5KpOnI7dMNpAXXyX4RgDkMKFzQ8LpxV1VUrP9a9AzyeEm5gQ5HJV-8D7uMoxaPSTlD1uqk6c0b64mEXjFRqQoxpAGdhlIby2lcQ72TSHqz-iDLFpRPW_aJ8mWXXAwSwU3rYsphnZsQyehwW_w.aJCRlVYfMrvdu2zwKWdOc1aDfJ9Dt3WeLubFuzypzZI&dib_tag=se&keywords=motorcraft%2Bfriction%2Bmodifier&qid=1757351042&sprefix=motorcraft%2Bfriction%2Bmodifier%2Caps%2C250&sr=8-1&th=1&linkCode=sl1&tag=fordt-20&linkId=8dadc76e205c6d45bea7f824143eaa15&language=en_US&ref_=as_li_ss_tl