Hi guys and thanks for answering. Well, it doeswnt seems like a contact problems of the HT leads or spark plugs since they both new (10K km) and original, and there are no problems at all during driving and at morning start (I woke up today at 6:00 just to check how the engine starts! at 10 it's pretty hot out there). No faults at all at the diagnostic checks. I checked the value of the water temprature sensor on hot engine and it was OK, like all the other sensors (I have 4E-FE engine book). I'm thinking the problem is leaking injector/s. When it's cold the engine starts with no problem - it needs more fuel so leakage is helpful. When it's hot the over-fuel is doing a mass. the engine is harder to start and the air-fuel mixture is not correct, this is why it takes few secounds for the engine to correct itself. The problem occured before the ultrasonic clean procedure and got worse afterwards, sorry for did'nt mention it at first post. I think the best solution for my 11-years-old-hard-life-200,000-km-Toyota are 4 brand new injectors. Cheapy cheap on EBAY. Thanks for the willing to help! Itamar.