I know, that some ECUs have been fixed by some TV/radio maintainers, but its not anymore work, what U can do at home. So, if U find such maintainer, U can ask, can he do that. Anyway its not so simple, cause i havent seen anywhere shematic about P7... Without shema and understand, how ECU function, its very hard job to evrybody.... Good point is, that MOST of those problems are caused by "cold weldings" in circuit board and if You look carefully surface with magnifying glass and good light, u can notice, what weldings can be cold ones. Surely U have to check also first that big connector of ECU, that there is not cold weldings/broken wires. I have lookeed sometimes close my P7 spare ECU and seems, that its very well coated with clearcoat against air/moisture, what causes plenty of harm in circuit boards. That Marelli (906) ECU i havent seem so close, but it can be harder to open and fix. I know, that just that P7/P8 is very good ECU, so i am wondering, if there is some COMPONENT broken. Surely it can also be reason for wrong function, but before that i would check all other components in injection system. 