My check ingine light came on, after getting it check out the code came back p401. The guy told me it was a bad egv valve. Is there any way to clean these? Also where is it located? And what is it used for?

 

What kind of truck are we talking about here. P0401 is insufficient EGR flow detected. If it is a 6.0L Diesel, your probably looking at an EGR valve. I change a few every week. You could try cleaning it I suppose, I have never. If it is a gas engine it could be a faulty dpfe sensor or a bad valve. I see lots of dpfe sensors go bad.
We just need more info.

 

Its a 1999 f250 v10 gas

 

Since it's gas, I would bet on the dpfe sensor. It senses how much EGR flow the engine is getting. If you have a vacuum pump, I would hook it up to the EGR valve while the engine is idling and pump it up. If the engine dies or goes rough, then the egr vale is working and the sensor is probably bad. You should also check to make sure the hoses on the sensor are ok. It could also be the EGR Vacuum regulator. It would be easy to fix if you had a scantool like at the dealership. My money would be on the sensor, though. If you want to post a pic of your engine, then I could point out the parts to you.