Vibration fading out, then returns

This happened to my phone as well. It would cut out every time I typed a text message and then come back randomly. Tapping the phone on the side would also bring it back for me. I got it replaced under warranty and when I received the new phone I realized that my vibration had diminished some on the old one before replacement. I had also done two FDR's which didn't fix it.
I don't believe I had the problem before ics either which is interesting.
This us a known hardware issue on some razrs and maxx's. It goes and comes. It happened on gb and on ics. But its not all devices. None of my maxx's do it.

Another common issue is the speaker cutting out... :)
faulty connection

I've been having the same exact issues with my phone pretty much since I bought the thing. I have done tons of research and I have even
opened the back of my phone to look at the vibrator and it seems like it isn't a problem with the software at but a problem with the wiring.
Like someone mentioned when you tap it against something it starts working agian the reason is because when you hit the phone it knocks the loose wire or loose connection back in place.. I hope this helps!
I have the problem on my Maxx and like all of you if I lightly tap it on my hand/desk/knee ect..will come back. Now a while back on a thread like this and I saw someone had traced it back to the vibrator not being properly lubed from the factory. He said he took the back part off and lubed the vibrator (to be honest I don't remember what he used to lubricate, it's been maybe a year since the thread) and after that he never had a problem, there were also a couple people in the thread that took his advice and they all agreed it worked. I never tried it myself though as I don't feel comfortable taking a part my phone.

Sorry I know this is very vague but hopefully it will point y'all in the right direction? lol Idk :)