Engine lite is on

You certainly have a fuel control problem (always lean). The first place Ford Diagnostics take you is to check the Oxygen sensors - all of them. Then they tell you to look for unmetered air. If you have a scan tool that can read PIDS, I'd check the MAF readings and the O2 sensor readings. Look for a large vacuum leak, air cleaner assembled wrong, messed up PCV or PCV hoses. It's likely that the MAF sensor is bad or very dirty. I've never successfully cleaned one - always had to replace them. It's an expensive guess. Low fuel pressure can also cause lean conditions as well as a MAP sensor failure. All of these components can give eroneous readings without tripping the Check Engine Light - thus the need for a scan tool that can read PIDs and a Technician that knows how to properly diagnose them.