just got back from a little road trip, hauled a car up the coast about 400 miles, dropped it off cruised around town abit got stuck in some traffic,refilled with fuel jumped back on the freeway with an empty trailer, cruising about 60/65 mph, everything was good for about 100 miles when the truck started to hesitate, then when I put my foot into it....nothing like the peddle was disconnected from the engine after a few seconds it hesitated some more, I looked out the side mirror and saw puffs of black smoke comming out the tail pipe????? crap I thought! when I let my foot off the peddle and slowly pushed back down on it it ran fine?? But after that when I tried to pass another car it would buck and puff, if I rolled into it easy it was ok. Then the MIL came on.
When I got home I put my scanner on it a it threw a couple of codes.
1) P0407 EGR sensor B circuit low.
2) P0488 throttle position control range

I don't have a clear idea as what the true problem is. another EGR solenoid? and or a gas peddle TPS switch? anybody out there have an idea what these codes mean any help would be very appreciated

 

for the p0407 code it could be that your EGR solenoid might be stuck and not opening all of the way, or just starting to get weak, with out a strong EGR signal, that is certain presence of exhaust gas in the intake system, the ECM throws a code, that's why folks in cal. can't do an EGR delete. the shops computer picks up the code and they know that the EGR systems in fail mode.
on the p0488 it sounds like the drive by wire throttle assy. may be getting worn. I had to replace the throttle assy. pedal in my 04 at about 175K the TPS switch is inside there and controls the amount of....well everything on these things. if you don't have one, get a good manual on your truck and it'll show how to test the TPS, and also give you a n idea what the codes are. you did not say which type of scanner you are using.
I'm surprised no one on this site has commented on this, there used to be a lot of very knowledgeable folks on here. it's been awhile since I was last on here. but I think that there was guy named mdub on here that was pretty sharp with these things. don't really remember...CRS 'ya know. good luck

 

P0488:

2004/05 Trucks with False EGR codes and/or Harsh Shifts/Gear Engagements:
Pickups built after 9-29-03 and Excursions built between 9-29-03 through 1-10-05 may exhibit EGR codes P0488 or P1334 with no driveability symptoms, harsh 3-2 downshifts in Tow/Haul, harsh 3-5 or 5-6 upshifts, or smoking during elevated idle operation. Additionally, 04 Econolines may also exhibit EGR surging (change in engine noise level), idle surge and low power, smoking, and rough idle following a cold start that corrects at operating temperature. To correct these conditions, the computer should be reprogrammed with WDS version 38.9 or 39.1 or higher (not version 39).
F-Series/Excursions: TSB 05-17-16.
Econolines: TSB 05-18-5.

 

great! thanks Heavy Assault: so the p0488 code is the EGR throttle position sensor located on the air intake horn correct.
but what about the p0407 code which is the EGR sensor B circuit low, shorted to ground. is there another sensor for the EGR other then the EGR solenoid and or throttle position sensor? or do I need to up grade the program in the ECM, and is this a dealer only thing? and this might clear things up.
@ doin my own: I have the auto enginuity scanner that hooks up to my laptop, I've loaded the current program for the 6.0 into it. it's great, I also have the program for my wife's 2013 Nissan in there too. it seems to be a very versatile tool and perfect for the do it at home guy for new cars with the OBDII systems, I've got 4 or 5 programs in there for friends cars too, for a few bucks I just get online and down load the current programs.

 

Hate to say it my books are for a 2006 so I can't give any more info. At least one would get resolved.

 

Did you ever figure out this problem mines doing the same at the moment wondering if it was ever valve or the throttle plate thanks.