Clearly if someone checked this out and found that these three things are faulty then that would be fine to fix the issue but it sounds like they are just guessing at the different components that you would need to fix this issue.
I doubt this is the idle control as that only regulates incoming air to make sure the engine does not stall. It is unlikely to cause a harsh engagement.
The MAF again is unlikely to cause this as well. Granted if they are not reading accurately then they can cause the engine to run poorly and that may cause the transmission to shift when it should not but if you only have a harsh shift then that again is unlikely.
If you would like to clean it and see if it makes a difference then here is a guide that will help with this:
You have a hot film sensor so they can be cleaned but if monitored then we would know if they are reading correctly. Basically you just watch the Hz or voltage on the signal wire and it should move smoothly up and down as you accelerate.
Where I would start is with the fluid. If this is dirty or low it will cause this issue. So I attached the info on checking the fluid and then we should change it if it is suspect at all.
Please run through this info and let's go from there. Thanks
Images (Click to enlarge)
Monday, August 23rd, 2021 AT 7:39 AM