The p0401 code comes on and off what should I check first?

 

Check the DPFE unit. They go bad quite often on these trucks. The EGR valve also sets this code. Check the valve and see if it is working. (Put vacuum to the top of the valve and see if it tries to misfire, if so it is good). The tube can also have a restriction.

These are what usually cause this code. Good luck.

 

Well one of the hoses on it was ripped on the end so I shortened it a lil so it wouldn't fall off may that be the problem?

 

Probably not. It most likely is that damn DPFE unit. They go bad and don't send enough vacuum to make the system work correctly.

Do you have a friend with a similar truck you could switch the DPFE from his to yours to check? Simple 5 minute check. If not pull the line from the side going to the EGR and see if there is vacuum there. If not then the DPFE is probably bad. Check for power to the plug on the DPFE first. That usually isn't the problem, but better to check than be sorry. Good luck.

 

And with replaceing this what should I notice?