I already know what it is. But where is it,on a 2002 4.2 f150. I've heard you have to remove manifold plenum.This looks like a difficult project. Thanx Ken

 

It's involved. Most difficult part is removing the rearmost bolts holding the plenum down to the metal part of the intake.
To illustrate, see photo below. Manifold plenum has been removed. This is from a 2001 4.2L V6 F150.
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Best write up I've found showing how to access the IMRC and what has to be disassembled to reach them. Here is a link to the article, go to the second page, step 46 for specific IMRC instructions.
P0171/P0174 Fix Procedure - Ford F150 P0171/P0174 Fix

 

Yes, that is the site I referred to, to do my recent repair & get the photo I posted. I never did figure out how to actually access the plastic bushings to replace them. As far as I could tell, my OEM bushings were working fine, so I shelved my new bushings & put reassembled everything without replacing them.

 

My son's '03 F150 got the P1518. The IMRC was located behind the motor on the back side toward the middle top side. I reached behind from both side just to feel the rods coming from the unit as I read that it could be worn bushings (that hold the rods in place where they connect to the "flaps" on the intake). The rod had fallen out of the flap on the passenger side. I treaded a piece of piture hanging wire through the hole where the rod goes. I then slid the new bushing thru the wire and seated it into the hole where the old one had been. I then fitted the rod back into the bushing. I did this all w/o taking anything off or seeing what I was doing. It's a bit tricky but it worked and saved a lot of time / money. The bushing was $10 at Ford dealer. I hope this helps someone else who is getting this code and just has a worn bushing. Takes about 30 minutes.

 

Just to be sure you know, the 1518 code is a signal the IMRC is stuck open.
It may be mechanical, or electrical from the sensor.
Check this out as much as you can before deciding on what to do.
Good luck..

 

i would like to see the picture of your upper intake-no photo

 

Can anyone help me my truck stalls as well I changed the iac and I still have the same problem I have a Ford f150 4.2 liter the code comes up is p1538 p1537 intake manifold runner 500 bucks a piece can anyone help me before I spend that kind of money

 

I also had tune up and still have the same problem

 

Wiiiiillllyyyyy.
The codes say the IMRC for both banks are stuck open.
That is their normal position until they are closed by the vacuum motors.
The codes don't say they must be replaced.
They are not the reason your motor stalls 'just being open'.
Get in there and check both sides to see what the situation is.
Both being open tells you the problem is common to both sides because both sides work at the same moment in time.
See what the problem is first or let some one else repair the fault.
You have to see what it is first before any action is taken.
The drivers for them are at the rear ends of the intake manifold both sides.
The stalling 'may' be another issue until you check things out.
Good luck.

 

Thanks Bluegrass that is good news!! I will take everything apart to see what the issue is wouldn't oxygen sensors cause the truck to stalls out?

 

Lack of air:
Could be the Intake Air Controller won't open, stuck or dirty.
Low fuel pressure, from clogged filter, fuel pump etc..


To much air:
An air leak that has shifted the fuel tables rich trying to account for the excess air.
*
Use of a Scanner to look at the live data will show one of these faults except the IAC stuck closed..
To check for this, if you start the motor and hold some throttle on and it keeps running, it is the IAC stuck closed or not operating.
Fix this first before the IMRC issue.
Good luck.

 

Thanks for everything Bluegrass the problem is the 02sensor down stream but I can't get them out I'm going to take it and have somebody heat them up hopefully that will do the trick