Everything was reset on Friday and I now have around 225 miles on it. At what point should I start to be concerned of an underlying problem. I ran into a similar problem two years ago when my truck would not pass emissions because a certain monitor would not run (can't remember which). I could not figure it out and another garage couldn't either. I resulted in going to the Ford dealer stealer. They found it to be a faulty thermostat that was making the truck run only one degree below normal, and it was not allowing the computer to cycle because of the problem. It took them a week of swapping parts and calling the Ford engineers in Dearborn, but they found the problem. And it only cost me $800.

I'm just afraid of another scenario of it being something I can fix, but only not knowing how to diagnose it first. I'm starting to wonder if the catalytic converter is bad. The truck now has 220,000 miles on it.