Shuts off while driving

Please help. My vehicle would usually trip off after about a forty five minute drive and that is usually after the check engine light has come on a couple of time at intervals. At a start again, it comes on and drive normally and the same thing still reoccurs until eventually it may not cooperate again until after a long period allowing it cool down. I have had to change the fuel pump in the process after which it worked well no matter the distance until last month on my way to Ibadan after being in traffic for about four hours with the engine running the problems started like before.
I am told it is an electrical issue so the electrician check and found nothing wrong so he suggested we clean the injector which we did and Hv not had the engine light come on again although I have not driven it on a journey of up to forty minutes after that experience for fear of the unknown. Please assist what could have being the problem. I also scanned it once but it did not indicate any faults. Could this be an issue with the fuel line?