Persistent code 27?

I'm coming back with something that you may agree with me on. I noticed that that when I disconnect and reconnect my fuel injectors, some of the connectors aren't gripping the injectors. I have to push hard on the connectors, when reconnecting in order for the check engine light to stay off for a few miles. Then, I can stop and go a few times before I get the same thing. I'm now supposing that those connectors need replacement. Seems like it's always on the back 4 connectors that lose their grip, causing a poor connection. What is your experience on this?