The truck has about 128k on it now. I don't think the O2 sensors have ever been changed out but not sure. Will a bad O2 sensor give a code if its out of range? If the DPFE is shot will it always throw a code? On the Fords can you actuate the diaphragm of the EGR valve easily or is it accessible? I'll take it apart this weekend but thought maybe I could do a quick check to see if it's stuck. If I replace the O2's, what brand, etc. would you recommend? Anyone know where to pick up the extended spark plug socket for the 4.6? Figured I better check them again. Let me just try to squeeze a few more questions in here!

 

You can test the the diaphragm with a vac pump - when the diaphragm is closed , apply 5-6 in Hg to the valve. The vacuum pump should hold vacuum -



If your without a pump - With the motor running disconnect the EGR vacuum supply line. Connect a hose and suck on it like your drinking a milkshake. If it's working your should become erratic or deflect - you'll notice change. If your diaphragm has been compromised , there will be NO change in idle.

 

Yes, always - that's if it's not within set parameters. When there old like yours are , economy suffers, your idle might roll a bit. Change the front two at least - Global Automotive is trusted ebay store if want good pricing.

Bosch, Berg & Warner, NTK's - They all work well. Bosch is stock (OEM)

Yes -PO401 usually, but that could be dirty ports or the EGR as well. No codes - don't worry about it.

Any supplier shoul carry those , I use two - one with a foam incert to remove and one without to install.

Good Luck

 

my gas milage went down 1mpg when i put new 02 sensors on. but thats probably because new 02's went on with the long tubes. egr delete and bbk 75mm.

 

Last night I disconnected the neg. battery cable to reset the computer in hopes it might pick up the misfire. At lunch today it finally gave me a P0301 code - misfire number 1. Apparently the plug on number 1 was crap - the insulator was burned discolored and had a crack in it. There were also spark trails all over the insulator. I put a new one in and it is running near perfect now. I think I'll still go through and clean everything up though. With the mileage it has - can't hurt. Thanks for the help guys.

 

yeh gotta hate it when u get a bad part!