Last weekend I replaced the intake gaskets on my 97 5.4l. I was getting 171 code and decided to go after the intake for the cause. So after I get done with the job I happen to see bright blue gasket while looking for the connector for the IAC via a mirror. I also can see a a bolt hole. This is one the passenger side. The casting on the head is marked RF75E-6090-C20A. Could this be the cause of my code P0171 coming back? Thanks in advance. I have an aluminium Upper Intake. Maybe the previous owner put a differant year 5.4 or 4.6 or for whatever reason changed the upper intake. Please help and thank you.

 

Welcome to FTE. i think you answered the question with the word Jasper.
i have never seen anything good come from the company.

 

Looking down thru mirror. It appears to be a port in the cylinder head of some sort. Truck runs great and idles perfectly.




Passenger side, back of motor near firewall




Casting on the drivers side cylinder head

 

looks like they put the wrong parts on the wrong engine.

 

AND....I have a plastic lower intake??? Anyone have thoughts?

 

another pic with the threads viewable in this one