Couple weeks ago I had an issue with my truck. I was driving and suddenly at idle it was running like my Camaro, chumpy and lopey, fuawking thing was stumbling and sounded like it had a huge *** cam in it. I didnt have any power loss, but it sounded like crap at idle. I had the code checked and it was something to do with emissions. I made a thread on here and was told the EGR needed to be cleaned or replaced and/or IAC. I couldnt get the EGR off so said forget it and just cleaned the IAC. Ran fine, perfect for a few hundred miles. Today I get a check engine light on and the codes are lean bank 1 and 2, 171 and 174. I did SEARCH and found that its most likely a vacuum leak. Before I go nuts traces vacuum lines, do you guys just think its the EGR since it seemed to be the reason of the crapping out way back when?

 

About the EGR - Pipe wrench and Cheater bar ( : - It depends on the numbers you had stored. I doubt it was valve.

Don't forget about the MAF. Specially since both sides are running leane.

 

May have over oiled the K&N. I will get some brake cleaner tomorrow and clean the MAF.

 

My '97 Expedition had the same codes, and after searching through this forum and others, it was determined that the problem might be the PCV Valve assembly. Namely the rubber elbow that is connected to the rear of the intake. I reluctantly went ahead and investigated and sure enough the rubber elbow in question was in fact leaking. Went to Ford, and was informed that the elbows are not sold separately but the entire assembly could be purchased for $48 (CDN) Went ahead and replaced it. Reset the light. And away I went!

Better and cheaper then replacing intake gaskets like my mechanic wanted to do.

 

You need to trace the problem (ha) from your PCV tube from the passenger's side valve cover to the intake manifold.