Yet another P0171 and P0174

[Zenonb]

Hello All,

My 2000 XLT with 178K miles has its check engine light on with P0171 & P0174 codes. Intuition tells me that I should replace the original PCV valve, if I can find it. Most of the forum posters seem to suggest that the manifold gaskets are suspect. I am wonder though, if I took ot to a shop, how would someone who knows what he is doing diagnose the problem. How far can I get with my code reader / parameter checker gizmo.

Any advice would be appreciated.

Thanks,

Zenon

 

[travelinman1962]

had the same problem

And i took it in to be diagnosed. It turned out the tube from the egr valve going into the manifold had a leak around the gasket that went into the manifold. That should be the first suspect. When air leaks into the manifold it causes a lean fuel mixture. If that is not the problem than it could be a more serious air leak. if it is the egr tube seal than that should be an easy fix. I put atv hi-temp sealer around the tube where it goes into the manifold and i haven't seen those pesky codes since. My explorer is a 96. I hope this helps.

 

[Zenonb]

And i took it in to be diagnosed. It turned out the tube from the egr valve going into the manifold had a leak around the gasket that went into the manifold. That should be the first suspect. When air leaks into the manifold it causes a lean fuel mixture. If that is not the problem than it could be a more serious air leak. if it is the egr tube seal than that should be an easy fix. I put atv hi-temp sealer around the tube where it goes into the manifold and i haven't seen those pesky codes since. My explorer is a 96. I hope this helps.

 

[Zenonb]

I appreciate your input. How did you know it was the egr tube? Were you able to hear the leak? You pulled me back into the reality of actually diagnosing the problem before starting to change things. I am still wondering though, how someone who knows what he is doing would approach this?

Thanks,

Zenon

 

[travelinman1962]

air leak

I appreciate your input. How did you know it was the egr tube? Were you able to hear the leak? You pulled me back into the reality of actually diagnosing the problem before starting to change things. I am still wondering though, how someone who knows what he is doing would approach this?

Thanks,

Zenon

The mechanic i took it to sprayed carburetor cleaner around the engine area while it was running and when he sprayed it on the tube the truck started to run rough. I would imagine those guys see a lot of these problems so they know what to check first. Sometimes they will use an automotive stethascope and try to listen to any air leaks. But the fast way is the carb cleaner. You have to be careful around the exaust manifolds tho or you could start a fire. Luck to you and yours.