Hey Guys - long time lurker, first post! Recently picked up an '01 4.2 RCSB 5spd (100k mi) as a DD. MAF was dead when I bought it, easy fix, and otherwise has ran great for the past 8 months or so.

Last week she died when coming to a stop. Fired right back up, but was stalling at stops.

Codes were the lovely P0171 and P0174.
The idle has always been rough, but otherwise drove great.

So I ordered all the parts to go ahead and do the isolator bolts, and plenum gaskets.

Early in the job, as I was removing the 'top half' of the plenum, the very last,,, and easiest bolt to get to (the one left of the TB as you look at it) spun free - wasn't unthreading.

These bolts thread down into metal 'sleeves' embedded into the lower plenum plastic.

So after much frustration I used a dremel to cut the bolt off (no damage to the upper plenum.

99% of the way through, the screw loosed in the sleeve, and I was able to unthread it by hand - like normal (sans all the cutting and cussing).


I know have a lower intake plenum half with a bad bolt 'sleeve'.
Is this fixable???, or am I looking at buying a new plenum altogether?

Can I get it anywhere besides the dealer/junkyard? I wasn't able to find an aftermarket source.

Also, I can probably figure it out, but if anyone knows the specs on the bolt I'll need to replace I would greatly appreciate it.

I did fix a couple lost IMRC bushings while in there, and will be replacing the EGR and PCV valve and elbows, and fuel filter.

Back to the plenum sleeve - fixable?,,,could I remove, coat in super glue, put back in, and use?

Also, are all the vac lines (aside from the brake booster) 1/4" in these trucks?

I'm currently down the aluminum manifold, have it all cleaned and ready for reinstall, just stuck here. I guess now is a good time to swap those fuel injectors too huh? - I assume a regular old Ford fuel disconnect tool is all I need?



Many thanks - great site!

 

First off, WELCOME LONG TIME LURKER!!(I did the same since I was driving "others" at the time
I would sand with 80 grit and use a good epoxy over superglue.
If you want to replace working parts, no one but your wife or wallet will stop you.

 

Thanks for the welcome, and suggestion!

Might go try that this evening. My lower back was hurting BEFORE I started this job. Quickly realized the sooner I accepted that i would be laying face down on my motor, the easier the job got.

Looks like my local junkyard has a plenum off the same year truck, so I have a back up just a couple miles away.

I'm thinking of replacing the fuel injectors simply cause I'm already in there. Glad I bought the imrc bushings, those are worth the $3-4 price to have working. The vac lines I want to replace since I'm already there as well. Won't have any easier access, and I plan on keeping the truck for a while - great shape and I got her cheap.

Actually bought the exact same truck but a '98 new off the dealer lot. Loved that truck, and should never have sold it. It's just a tool around town truck for me, my DD and hauler and want her tip top. My mustang is my go fast fun toy

 

I would not replace the injectors. there was another guy on this forum or another that had the same Lean codes you did, and replaced all injectors, all Coils, and spark plugs with new. 3 of the new ijectors was worse than the ones that was on his truck and the cheap coils he put on was crap. So after all that he ended up using most the same old parts he took of. I have 270,000 miles on my stock injectors, and stock coils. If is not broke or bad don't mess with it, you could open another can of worms doing that. I would replace the vac lines while you are in there, but the injectors are not hard to change if one go's bad.

 

I probably won't replace the injectors, I don't have them in hand right now, and it's not really necessary - but soooo easy to get to right now. My truck only has a single coil, and i replaced that along with the plugs when I got her new. Sounds like the other guy just had bad luck, or didn't install properly.

Looking to replace some vac lines too.

Got new bolts from Ford ($4 for the 'short' ones, $29 if you want the 'long' ones that have the post the spark plug wires go!)

JB Welding the sleeve back into today. Hopefully reinstalling it all tomorrow evening or Friday.

 

ALL FIXED!

Finally got her back together on Saturday, and she idles beautifully now, no stumble.

Check with my programmer, and my LTFTs are both at 0-1%! (previously were +15% or more)
Plus my STFTs have gone back to normal too - hovering around 0 most of the time.
Previously with the air leak I was seeing -25% (cutting as much fuel as possible) when ever I was off the throttle.

I don't quite understand that though, I always suspected an air leak - even before I got the P0171 and P0174 codes. However seeing that my STFT would rail it self at negative (-25%), I was wondering if perhaps I had a leaky/sticking injector that was dumping in too much fuel - thus the computer was cutting fuel as much as possible.

However, I guess the LTFTs were telling the truck - they were adding fuel = air leak.

Replaced 2 IMRC bushings while in there too. Only one arm had fallen, but I did both to be sure (the easy to get to ones anyway).

Now the truck idles, and pulls much harder in the upper rpms where before it would fall on its face.
It does seem to have less low-end torque then before the fix - but before the fix, that's all it had - low end pull,,no top end.

Question - i should know this, but it escapes me - what is the that thing called that plugs into the passenger side valve cover with the 3 vac lines coming off of it? Think it goes up to the PCV on the throttle body. I noticed mine slips out of the valve cover super easy - should I replace it, or is there a gasket I'm missing? Doesn't seem to twist lock or anything, just presses in.

Thanks!