Av here you have several details and many things to review yet, because the information you give is not very good.
First: Dodge Neon, erase all the failures of the computer's memory and you have failed, when the Czech Aga specifically what code gives you, and tell us if it stops the vehicle or not, that raw gasoline may be lack of air by IAC in poor condition or dirty, or the TP does not fall as it has to be for a damaged track.
The Atos goes out or accelerates, if you do both things, it could also be an IAC problem that does not regulate correctly but you do not tell us if it is injected or carbaded, but you could do a test by taking out your thermostat if everything goes well buy the temperature sensor.
Third, caravan check if you have a spark first if it injects fuel, if there is no spark they can be several different problems and only no fuel is problem with the pump or relay of it or with the computer blokeo. Choca first and let us know,
luck with your workshop, just have it without fear.