Mk7.5 1l Ecoboost Shuddering When Coming Off Throttle.

[Bongo2296]

After hard acceleration then letting off the throttle, my Fiesta will often shudder a few times when coming down the rev range instead of smoothly coming down as expected. Is this normal, or is it a problem? Any tips would be appreciated, and whilst I'm here making a new topic I'd like to know how to know when to change spark plugs. I bought my car used so I have no idea if they were changed when they were meant to be.

[cjay1]

Ford advise every 3 years or 37500 miles but if the engine is running well and no codes triggered happy to leave them longer currently over 5 years 21000 miles on current plugs and running like new.

Mine goes up and down the rev range smoothly so there could be an issue with yours 

[Eng_Ahmad1986]

if the rpm is going down smoothly and you feel shudder in the car body then I would check cv joints, the inner cv joints particularly for any play, I would check also engine and transmission mounts.

do you hear any metal to metal knock when you start to move from stop forward or reverse ? if so then I would definitely check the cv joints and the mounts.

this engine is very torquey , it has a habit of damaging the lower transmission mount , they call it ( the dog bone mount ) I have seen many cases like this, worth checking