I know p405 means low exhaust return circuit or something like that, but I've tried just clearing it but it comes back on within 10 seconds of restarting the engine. What do I need to do to correct this problem? Also think it's causing my truck to use more gas, which really sucks.

 

Have a read through this:
P0405 - Exhaust Gas Recirculation Sensor A Circuit Low

And let us know if you have any questions.

 

That does help out some but by that sayin that, should I replace the EGR valve or what? Just check the wiring and connections?

 

You could try cleaning it first:
EGR Valve Cleaning

Then you could ohm out the wiring between the valve and the PCM.

 

Alright I try that. Thanks

I have one more question for now. If I have a dirty/bad EGR valve that would cause higher fuel consumption right? Also would explain the black build up coming out of the exhaust. Carbon build up right?

 

I cleaned it out yesterday and it worked great. I cleared te code and never came back on, so that was good. Plus the motor sounds a little bit better. Thanks for the help.