406 Petrol performance issue

[ValG]

Peugeot 406 Petrol, sedan, 2002, 2000c, 200,000 km. Her performance seems to be mood and weather dependent. She hates dry and hot weather (Israel), the engine turns noisy and responds poorly to the accelerator. Once i did air-intake system cleaning, changed the plugs, reset the errors - she ran like a new one! However, a week later, she became dull again (weather doesn't count). Sometimes, especially in the evenings, she runs reasonably well - but NOT like after that maintenance. Air, oil filters have been changed. Servicemen can't find anything, - i do have "Antipollution Fault", which is contributed to the stalled Air Pump (it runs on cold engine). I don't expect a 200,000 km car to run like a new, but she DID run like a new one, which means that the engine itself is in good condition. Any idea, where to look for the problem?
Cheers,
Val

[teamster1975]

Welcome in Val!
Sounds as though one of the sensors is faulty; I'm not 100% sure but there's the coolant temp sensor, MAP sensor and TDC sensor off the top of my head.

[ValG]

Cheers, mate. So, resetting the errors sorted out the problem for a while... There are other symptoms too, like random pinging, rough idle, engine vibration, hesitation - You name it! Seems like each sensor may be the one to blame. I reckon I'll have to ask Peugeot servicemen to read and analyze the parameters, rather than look for the errors. What do you think about full fuel system cleaning? Some say it might actually do more bad than good by damaging rubber parts