I don't think that's it, because i did that not to long ago. I'm thinking the dirty fuel injectors may be the cause. I remember, when i first got it, at 105k miles, the check engine light came on. It was the fuel injector code flash. I ran a couple bottles of fuel injector cleaner through it, and it solved the problem. It now has 180k. The check engine light has not come on since. Edit: I just saw where you have the same number of posts' as me. And, you joined almost a year later.