Toyota Rav4 (BJ95) starts to buck – who can help?

Hello, recently the Toyota Rav 4 (built in 1995, about 240,000km) of a friend starts to buck. Since he and his free workshop don’t know any more, I thought that I could possibly get the one or other useful tip from the MT forum. The problem can be described as follows: The car usually starts normal. However, the problem appears after about 15-20 minutes driving time, because the gas is not properly accepted and it comes to ignitions, so that the engine goes off. If the engine is still on, it should also be noted that there is a power loss. When starting again, it takes a certain time until the engine is running properly again. It is very noticeable that this problem arises when the car was driven before and this is started again after a short time. (So it has not become cold yet) In individual cases, the car does not jump again after it has gone out. but an employee on the phone rejected it directly on the grounds that nothing would be stored there if no engine control light was burning. (I am used to it by the way of my C-Class, since errors are also stored there, if no lamp is burning) The workshop master from the free workshop then started to switch to the spark plugs, which did not bring any change. He told me that at the 1st spark plug oil vo However, this could also result from the fact that the spark plug was not tightened enough. After that 1 set of ignition cables was replaced. However, this did not remove the problem. Furthermore, the throttle valve was cleaned and the contacts in the ignition distributor were sanded off. Since 3 question marks were also visible in the face, my friend initially stopped the project to change the ignition coil, ignition distributor and ignition distributor fingers, since no clear diagnosis was found. But this can only be a coincidence. And now the question to you: Is there possibly someone among you who has had this problem before or has heard about it? Or does someone know which direction to go in? Thanks in advance