Sponsored
I'm sure others will be of more help, but I would check the spark plugs. I was having a similar issue on my Mustang. It wasn't throwing codes or anything and I had to go to 2 dealers since the first didn't find the issue. Ended up being a bad spark plug for cylinder 3.
I would say more in line with the air ide motor are dirty throttle plates, Doe's the check engine light come on? if so there should be a stored diagnostic code.
Sorry meant to say Idle Air motor {IAC} you can un plug it while engine is running and it should maintain base idle if not next steps would take a can of carb cleaner and spray clean the throttle body flapper with engine off using your finger and a rag.
- First Name
- Scott
- Joined
- Nov 19, 2025
- Threads
- 0
- Messages
- 180
- Reaction score
- 414
- Location
- Nampa, Idaho
- Vehicle(s)
- 2025 Bronco Sport Badlands, 2025 Bronco Sport Badlands Sasquatch, + 4 Stangs
Have you ever replaced the Engine Air Filter?
What happens is the throttle plate gets carbon soaked when the engine gets shut off and causes bad idle issues to where that IAC motor starts surging which causes stalled issues.
There's just enough air flow at closed throttle to pass by that throttle plate and when it's dirty idle issue happen that's always the first thing we check before anything else.
There's just enough air flow at closed throttle to pass by that throttle plate and when it's dirty idle issue happen that's always the first thing we check before anything else.
As far as I know, idle air control motors went away when electronic throttle control became the norm....around 2004 for Ford (at least in the Explorer that was the year of the transition).
- First Name
- Tom
- Joined
- Jun 7, 2021
- Threads
- 37
- Messages
- 870
- Reaction score
- 1,069
- Location
- Los Angeles Metro
- Vehicle(s)
- 2021 Bronco Sport
You're correct it's a complete electronic throttle body now, drive by wire i still would try cleaning it and see if any improvement.
This is good advice. Check for codes, look at short term and long term fuel trims with a generic scan tool. They should be within 10% of nominal values. If not, that can be indicative of something going on with air or fuel (vacuum leak or possible issue with fueling). Could be EGR valve coked up and not fully closing. Could be purge valve not fully closing.
I suspect @thomasm23 is asking about refueling to see if there is a possible issue with the purge valve being stuck open or maybe a bad tank of gas (contaminated or dirty - possibly plugging the filter). If it's a purge valve not fully closing, additional fuel vapors from the tank and/or canister can be pulled into the engine resulting in overfueling (liquid fuel plus unexpected fuel vapors if the ECM is commanding the purge valve closed but it is not fully closing). Lots of fuel vapor is generated during refueling events, so if it's purge valve related, it will usually be worse after refueling.
A similar condition can occur if the EGR valve doesn't fully close - except instead of excess fuel vapor, you get excess EGR, which is not typically helpful at idle and usually results in poor combustion.
Cleaning the throttle body probably can't hurt, but some have a coating on them that is not supposed to be removed so be careful there. In addition, there are TONS of fault codes attached to the electronic throttle body (redundant throttle position sensors, etc.) and ALL kinds of diagnostics - both OBD and torque security faults. If there was something wrong with that, I would expect a fault code. When companies went drive by wire, it came with lots of lawyers attached. Hence, the need for all types of safety checks to ensure the throttle never opens when it's not supposed to.
Here's a question. What was done to the vehicle just prior to this issue first showing up? Was it serviced or was any work done to it? Did you drive it off-road and run over something or do you recall hitting anything on the road? Just asking to see if you can correlate the problem to an event. That's often helpful in trying to find the source of the problem.
Good luck.
If the vehicle is connected to the Ford app, I can pull the last 60 days worth of codes with the VIN. I would assume the dealer looked at that already since they have access to everything I have access to and more.
- Thread starter
- #14
I cleaned the throttle body, but the problem is still the same. However, I disconnected the MAP sensor and the vehicle started running fine. I replaced the MAP sensor, plugged it back in, and the problem came back. If I leave the MAP sensor disconnected, the vehicle runs fine.
- Thread starter
- #15
The vehicle was scanned and no fault codes were found. The check engine light is not illuminated either.
It starts normally regardless of the fuel level, whether the tank is full or nearly empty.
Sponsored