I have a 1998 F150 with the 4.6 in it, just rolled 80k. Well I decided to clean my EGR Valve, and believe it broke it in the process of doing it. After cleaning it, about 25 miles later my CEL comes up with codes P0174 and P0171, both banks running lean. I was going to replace the EGR hoping that would clear up the issue but is there anything else I could have messed up to cause this?
Thank you!

 

Both banks lean is almost always caused by a large vacuum leak. If you ruptured the EGR diaphragm that would do it.

 

So basically if I replace the EGR and reset the light it should go away?

 

You can suck test the while @ idle to determine correct operation. Pull the green line while @ idle. Attach your own scrap peace of hose to the valve.

While @ idle, suck on the hose like your drinking a milk shake. Engine should almost stall. This confirms correct operation.

If the engine idle does not deflect at all. The diaphragm is compromised and you need a new valve.

__________________________

Keep in mind, you don't have any EGR DTC's. IMO, your valve is operating as it should.

Your DTC's point to a PCV leak back by the firewall.

 

Alright I did the suck test with a straw (not too many resources at college) ha and the idle did decrease, could I have effected something else by cleaning the EGR, because the code came up the day after cleaning it. I felt the PCV line and it did feel hard, i would assume it should be soft. Correct?

 

It's not the EGR. Your PCV line needs to be checked for leaks and pin holes. Not how hard it is.

Back by the firewall and where it plugs into your intake. Needs to be checked thoroughly.

 

Well back on the issue. I replaced the PVC line and valve and was was great for about 50 miles then my cel came back on and threw the same 2 codes, both banks running lean. Any other suggestions?

 

Did you use a MOTORCRAFT PCV valve? Did you replace the rubber elbow at the back of the intake?

 

yes it was all replaced with motorcraft parts and I replaced the entire assembly