I have this Peugeot that gives me the codes P1336, P1337, P1338, P1339 and P1340. Cylinder Failure. I changed coil check catalyst plugged spark plugs change O2 sensors.
When it accelerated to 2500 rpm the engine light flashes and cuts the injection into two injectors and turns on the catalyst indicator.
Valeo injectors? 99% Faulty injector they are rubbish. Do not clean them you can not repair them. Just swap position of injector to locate the faulty one and buy a new one
P1340 points to a problem with cam/crank syncronization. The fact that a severe misfire condition is detected at higher rpm may indicate a problem with the reluctor and/or sensor. Scope the cam and crank signals both at idle and higher rpm and watch out for irregularities in the signatures.
I never worked on a Peugot, but all those codes seem to be centered around the crank sensor. I would follow Juergen's idea and scope the crank at idle and higher speeds. Perhaps the tone ring is damaged or floating at higher speeds. It should show up on a scope. One other thought is, is there any type of crank sensor relearn on these vehicles.