My 2006 Magnum RT 5,7L is throwing a P0404 EGR problem. This happened not long ago and I replaced the EGR valve and problem solved. Do EGR valves go out that fast? Also I put some older fuel in it. (Wanted to get it out of my motor home and burn it) Fuel looked good, smelled good and ran fine in both the motor home and Magnum. Could this cause a P0404? HELPC

 

1. Did you clean the tube from the EGR valve to the intake manifold?
2. What octane is that fuel?

 

No, I didn't clean the tube. I will do that. I use low 87 octane. Been using that for 100,000 miles and no problem. But the old gas may have lost some octane.

 

Even though 87 is considered "acceptable", 89 is the recommended octane for the 5.7; failures have been linked to prolonged use of 87 in the early 5.7's. Also, how old was that fuel? Gas doesn't really lose octane, but it DOES turn into varnish...87 octane tends to be the **** gas anywhere you go. I would try 89 for a while after you check the tube (you may have to clean and/or replace the EGR valve again) to see if the engine feels better. You will notice it is peppier since with 89 the engine won't have to pull any timing.

 

The old gas was 87 and about 2 years old with stabilizer added. It had no discoloring or unusual odor. I had about 1/2 tank left so I topped it off with 91 this morning. Going to clean the tube this afternoon.

 

Cleaned tube even though it looked fine. Replaced EGR valve even though it was not that old. Cleared code and its been fine. I think the old gas may have been the problem.