My Engine shaped light for the emisions system has come on so I checked my gas cap and it was tight. Then I ran almost all the gas out and put good gas in and engine treatment and it still wont go off. the truck is still running fine just seein if there are any ideas of what else could be the problem.

 

Go to advance and have them pull the codes

 

The PCM (Powertrain Control Module) has indicated a fault and is storing a code. As the previous post suggested, take it to a parts store that reads codes (for free). Then put this code into a google search box. You'll get plenty of hits that will describe the code, along with suggested faulty sensor(s) to check/replace to correct the problem.

 

One thing ya might wanna check out is getting an ELM327 module. I got one a couple months ago, and it is pretty sweet! You can pick them up off of eBay etc. for $20 on up to $100+, and it plugs into your ODBII port and via Bluetooth transmits your vehicles data to your computer, or to a smartphone running a compatible app such as "Torque". You can pull codes, as well as reset them. In addition to that, you can also get real-time data on your truck, including horsepower, torque, acceleration figures, temps, pressures, fuel economy, and the list goes on and on. You can also setup custom alarms based on any data you want, high temp, low fuel, anything the device can pull from the ODBII basically. It has WAAAAYY more info than I could ever hope to use or even interpret. But ya can't beat it for the money (fyi I got mine for $0.01 + $19.99 shipping and it works great)...

 

We just went through all of this, had to replace oxygen sensors. Seems to be ok for now. Got a cheap code reader from NAPA, narrowed it down pretty good. Reset computer, time will tell I guess. Good luck!