How hard is it to replace an EGR Valve on this motor

 

If you remove the doghouse , that should make it a lot easier to remove the EGR valve.

 

now what 99 E 150 5.4 L pulled codes P0174 P0401 P0171changed the EGR sensor still runs bad. Push on gas and it sounds like you are doing 70 mph but you are only doing 40mph then kind of lunges and takes off what do I look for now

 

As you probably have found, the PO171 and PO174 suggest a lean condition in both banks.
The PO401 suggests insufficient EGR flow.
An EGR valve that is hung up could give the lean condition among other running problems. Even if the controls call for more EGR and it is defective or the passage is somewhat restricted you could get the insufficient EGR flow.
Did you or were you able to remove and check out the EGR valve itself?

 

no not yet I don't have a big enough wrench Anybody know what size it take I see the two small ones but there is a pipe with a big nut that attaches to the valve looks like over an inch in size need to know size so I can go get a bigger wrench

 

I cleaned theMAF and IAC and it does runs better but when you stop it idles bad and some time will just stall while sitting. Thinking if I should just bite the bullet and buy a new MAF sensor (already cleaned it twice) or buy a new IAC or both What say you which one first or both

 

really thinking my main problem is EGR valve I unpluged the MAF sensor and drove it it seemed to be about the same. Have already replaced EGR sensor. think next step is new egr and clean ports, not saying the MAP will need to be replaced later. But right now everything ponts to EGR valve

 

went for a test drive tonight. it ran ok when it got up to about 55 mph and started to chug a little bit let up on gas then push on gas ran a little smoother you just can't push on gas hard and expect it to take off like it use to. talked to a mechanic on way home he said he never has any good luck cleaning MAF said just replace it