I had a problem that wasn't a million miles from yours, have a look at post 20 in this thread. I detail the problem I had and what eventually cured it, it caused no engine management light, caused no fault codes to be logged. Once I changed the part the difference was like night and day, I don't know if it'll help you at all but good luck.

https://passionford.com/forum/ford-f...i-problem.html