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Category: Ford
Satisfied Customers: 26627
Experience:  ASE CERTIFIED TECHNICIAN ADVANCED LEVEL SPECIALIST. Wisconsin certified emissions state inspector
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I have a 2004 f150 4.2l heritage xl with a lean reading.

Customer Question

I have a 2004 f150 4.2l heritage xl with a lean reading. I've cleaned the maf sensor. I'm trying to locate where the vacuum hoses would be and also the intake gasket location. To check there. Unless you would think there is another issue.
I also don't know where the o2 sensors are. Bank 1 and 2
Submitted: 1 year ago.
Category: Ford
Expert:  Kenny Z. replied 1 year ago.

Hello, my name is***** and thanks for your question.

When you say lean reading, is this from codes or fuel trim levels? If so what are the codes and what was the engine temperature in the freeze frame data if you have it?

Customer: replied 1 year ago.
P171 and P0170
Expert:  Kenny Z. replied 1 year ago.

P0171 and P0174? was there any freeze frame data present with the codes?

Customer: replied 1 year ago.
What is freeze frame data?
Expert:  Kenny Z. replied 1 year ago.

Freeze frame data is a data snapshot that shows PCM data at the time the code was set. Most scanners can retrieve this data. Need to know engine temp at time of fault.

Customer: replied 1 year ago.
It was normal. Between hot and cold
Expert:  AMEDEE replied 1 year ago.

Hello and welcome! My name is ***** ***** I can assist you with your question. These lean codes are very common on this engine. The most common causes are a bad mass air flow sensor and or an air/vacuum leak. My experience has been a vacuum leak between the middle intake plenum and the lower intake manifold. Ford has revised parts to cure the problem, consisting of new "isolator bolts" that bolt the middle plenum to the lower intake, and new "port gaskets" (o rings) between the middle plenum and lower intake. There is also a TSB out about this. It is TSB number 05-22-6

Expert:  AMEDEE replied 1 year ago.

Remove the upper intake and replace only the port gaskets and isolator bolt assemblies. The new isolator bolt assemblies use a rubber material that is green in color, do not install the old isolator bolt assemblies with the black rubber material.


Port Gaskets.. 1L3Z-9H486-AA

Isolator Bolts.. 3F2Z-9S479-AA

Expert:  AMEDEE replied 1 year ago.

Hello! It's Amedee from just answer.

I am just checking in to see how things are going and to see if you need any further assistance?

Please let me know and I will be happy to help!

Expert:  AMEDEE replied 1 year ago.