1998 4.2 f150 175,000 MI. I have to replace the IMCR. How difficult of a job is it? Any tips? Any how-to videos that you know of? Do I have to remove just the upper intake? Any advice would be helpful thank you.

 

You need new IMRC grommets. The little white clips that hold the actuator rods where they're supposed to be. They have to be replaced anytime the actuator rods are removed. They are also pretty much the sole point of failure in the system.

 

Here is your other thread. I thought that the broken/missing grommets caused lean codes, not stuck codes. And 1998 is not like 1999 and after. No idea what the answer is, just doesn't seem like the later IMRC issues with the grommets. And aren't they called bushings in 1999 and on?


https://www.f150forum.com/f6/help-obd2-codes-509349/

 

p.s. there's not a ton out there about the 1997-1998 IMRC. It seems clear that the valves are vacuum actuated though. Some people remove the vacuum tube and suck on it to see if the vacuum valve solenoid is working or if the valves are really stuck. The Rockauto links I posted show what the valve looks like and the arm that moves the valves. Find that first.

https://www.rockauto.com/en/moreinfo...pt=10776&jsn=9

 

My pro tip is to not replace the actuator and just replace the grommets. The actuators are solid. I explained how grommets cause these DTC's in the other thread.

If just the outboard grommets on the intake manifold are broken, the job can be done fairly easily by just snapping in new grommets in the intake sides only without removing the intake or anything else. The job will cost you about $5. Use grease to stick the grommets to your finger so you can get them in place.

 

What’s leading to this conclusion? The IMRC motor itself is almost never at fault.

I believe the earlier aluminum intakes have vacuum hoses to start to rot, but you wouldn’t “replace the IMCR” over that.

I would seriously check compression and oil consumption. I replaced the IMRC and grommets on my ‘03 a few summers ago (2018) and realized the intake was a bit oilier than the first go-round back in 2010. All that work to realize that oil is likely getting passed the rings and forcing those butterflies open and tripping the “stuck open” code for bank 1. This wouldn’t be a huge reach for a 23-year old engine. Mine has 276,000+ miles, so I get it.

 

Post 18 in this thread describes what I'm not clear on. One's vacuum, one's electric. Checking vacuum is super easy.

https://www.ford-trucks.com/forums/5...cuators-2.html

 

Make sure you buy the motorcraft clips to replace the old ones with. You might have to go back and do the job again if you don't.