Logically, when using such cleaning additives, it washes away all the layers of whatever you already have on the injector points and more significantly on your valves.

When that happens, its no longer the same as you had them before, and thus the engine reacts with confusion as its not able to configure and compute the control of fuel mixture.

After a while it should be back to normal albeit a little rough conditions. Tuning may help, and that would be the cheapest start. If indeed the cleaning has got right to the injectors to the point that its leaking (after the cleaning - such an irony), then it may have to be replaced.

Is the vibration still as aggresive and not toning down?

The above is my common approach, and perhaps the expert techs living in this site may be able to correct my understanding if I have strayed.

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... Kerry

126 tailed by a 203, 129 leading the pack.