The PCV hose may crack, causing the vehicle to idle roughly, this may or may not illuminate the Check Engine Light.
Car Problem Reports
Ford Expedition Rough Idle Due to Cracked PCV Hose
Ford Expedition Problem
Engine Affected: 5.4L V8
Average Mileage: 134,947 mi (122,100 mi - 155,982 mi)
Visitor, 2000 Ford Expedition, 5.4L V8, 136,000 mi
Rough idle, stalling on my 2000Expedition. Code came up as PO171. Found a leak in my PCV hose at bend. This is a Ford only part. Went to local Ford dealer and ordered the hose with the PCV valve included. Replaced it myself. Problem solved.Ford part # 2L1Z6758GA.
Visitor, 1997 Ford Expedition, 5.4L V8, 122,400 mi
replaced entire pcv hose assy including valve
Visitor, 1997 Ford Expedition, 5.4L V8, 155,982 mi
I had extremely rough idle and most of the time it would not idle. I replaced the PCV plastic line with rubber hose. It has fixed the problem.
slight missing at idle. getting code p0171 and 0174. firstname.lastname@example.org