new engine

i have had to have the engine replaced 2 times before it ran "o.k" i was told that when there computer did it it did not put a cylinder in and i was only running on 3 and the second time they just told me a computer glitch but i am tired of computer made engines and that always being their excuce but from what my mechanic has told me it is might be 3 new engines!!! so i don't think they have gotten any better i replaced the engine just 6 months ago.