[K Dew]

I own a 2006 Acura MDX and have had to have the valves adjusted twice as it continues to slip into running too rich. The first time was at 43K miles and now at 87K miles.

What is potentially causing this? And, should I have any concerns.

 

[C25A1guy]

It's not something to be entirely concerned about. I've noticed that it just seems as if some engines tend to keep their lash adjustment better than others. As far as what causes it, I'd have to tell a story of the design of the engine's valvetrain.