1998 navigator

[Raleigh Joe]

I have a check engine light on and the diagnostic codes are P0171 and P0174. Left and right bank to lean. Any suggestions?

[pro-five-oh]

Examine/change your spark plugs first of all. They are platniums and last about 100k before they need to be replaced.

Oh, and welcome to Lincolnsonline. smile.gif

[Steve L]

Look for a vaccum leak on the PCV lines going to the upper intake manufold. There is a thin rubber connector where 2 plastic lines splice into. I will have a hole in it.It will be soft and spongy from oil vapors degrading the rubber. Go to the auto parts store and get a large plastic vaccum tee and some hose and remake this connection. Try to keep the tee the same size as the plastic tubing. No restrictions. This is a very common failure on fords and lincolns from 1995 and up.

[Johnne77]

My Navigator just did the exact same thing, and read those exact codes. The PVC replacement is the exact problem solver. It cost me about $300.00 to repair it. null

[Raleigh Joe]

Thanks for all who replied. Steve L you were right on the money. The hose going into the intake manifold from the pcv valve was cracked. I replaced it and the problem is no longer present. Thanks Steve.