I have a 6G72 TF Magna. At city speeds, when you back off to engine brake, at about 1600 to 1800 rpm it has quite a hesitation as though the engine has cut out but then it picks up OK at low to idle rpm.

I know back in the late 80s & 90s manufacturers had this great idea to cut the fuel at such revs so as to improve fuel economy. They even did this on carburetor equipped cars with a separate solenoid operated needle fuel valve.

Recently, I had the inlet manifold off and I set up the idle stop (I think that what it is called) on the throttle butterfly valve, as it was conveniently exposed. I used a feeler gauge and set it as the manual prescribes.

However, I think the engine cut out feel has sometimes become more of a jolt, at low speeds.

I'm wondering if I should open it up a little more as it was a fraction wider than what the manual said it should be.

Also, the centre muffler section has just developed a hole in it so possibly it is a loss of back pressure enhancing the deceleration jolt.

Had anyone had a similar experience?

That would be the TPS adjustment.

I think you are correct. My mind is a blank at the moment as I'm fixing another brand of car and I am in trouble for not turning the stove off in time to burn the soup my wife just made.

I remember that I found a correct thickness piece of metal and bent it to fit. Yes, then I marginally adjusted the TPS as the original dob of sealing paint was broken indicating it has been adjusted before we purchased the car.

Do you think that's the issue. Should I adjust it to open early or late to reduce the engine lag/cut out feel?

TPS settings tend to drift with age. Best to read up on how to adjust it in the manual, using a multimeter. That will also tell you if it is still working correctly, it may be worn out or broken.
Sounds like it is dropping to the idle setting too early, turning it anticlockwise slightly may help, but the multimeter method is your best bet to get it spot on.

Hope you survive the consequences of burning the soup. It's one of the big no-no's of married life. lol

Yes, I did use a mulimeter with buzzer so I could hear exactly when it made contact. I think it is set as per the manual but possibly the manual setting is not the best for driveability or it has changed somehow after I put the manifold and other bits back on. I think I did it without the throttle cable connected so possibly the tension provided by it has something to do with it all.

The throttle stop screw should never be touched for starters

The manual set up is perfect for driveability, if set correctly you will not have this issue or it is caused by something else.