Like a lot of people, I have dealt with the 1174 & 1171 codes. Replaced the MAF, replaced the O2's all vacuum lines etc.
I took my 04 into a brake specialist as my brakes were really performing very poorly. He said that my brake booster was shot and had a vacuum leak. Did not charge me, which I thought very cool. I had recently replaced the Master Cylinder so I knew getting to the booster was no biggie, just messy. I almost had a heart attack when I looked at a new booster ($500). Naturally went to AMZN hoping it would be cheaper. New was not but a re-manufactured one was about half. Came with a warranty, so i thought okay I am in business. Installation was pretty easy, especially with the help of buddy who is a great wrench turner.
About a week later, I realized that I had not had "the codes" since installation. Hmm... could this actually be the source of all my troubles for so long? A slow leak that got bigger and bigger over time?
Fast forward to a month after installation of reman booster. I was travelling on a very dark country road when Bambi decided to pop out and stand pretty much in the middle of the road, giving me the finger. I hit the brakes really hard and left some rubber on the road.
Immediately following this, noticed my brakes were really bad again. When I got home I found that one of the bolts on the reman brake booster has stripped and knocked the MC off center. Now I stomped on the pedal, and had done some many times before with the OEM booster, but holy smokes, the POS reman almost got me killed!
Sent the POS back to AMZN, and got a Lucas OEM from a dealer about 20 miles away. Installed and all good, including no codes!
The moral of this long tale of rovering is the following:
1) A bad brake booster may be the cause of your 1174 &1171 codes
2) Under no freaking circumstances buy a reman brake booster.
3) I know we try to cut the costs where we can, but the brakes are not the place to do so if you have lots of deer and poorly lit roads.
Here endeth the lesson.

 

If it's a reman then the bolts shouldn't have been replaced from when Cardone got the booster. Either you got one and the bolt just happened to be DOA, perhaps a hardening error, or the OEM unit would've done the same thing. All the bolts they use for those things are probably cheese grade anyway.

Sorry to hear about that experience. Pretty rough. I still don't think you can blame the fact that it's a reman though. They do bare minimum on those reman units. Clean them, replace the rubber bits, throw on a coat of paint, etc. Hell, I've gotten reman CV axles where they painted over the rust on the outside that flaked off during install. They're not going to put for the cost of replacing hardware unless it's damaged.

 

As you point out, they do the minimum on remans to make them sellable. That to me really means there is little if any QC. Since I am not the only driver of my D2, I am not going to take another chance.Trying to find a reman brake booster is tough to start with. I looked at a bunch of websites and they were all out of stock
I am beginning to wonder about the quality of auto parts from AMZN. So many of us have purchased O2 sensors that have been junk, MAF's which have been junk and now this POS. I am going to forgo AMZN as a parts source when possible.

 

Did your buddy overlook the poor thread condition when installing the booster?
......

 

Installation of the brake booster is best accomplished with two sets of hands. I fed it thru the firewall while he locked it down. I was actually using the bolts to shift into position. I did not see or feel any issues with the bolts.

 

Maybe your buddy over tightened the nuts? I dunno, sounds like a fluke to me.

 

I have an '03 with the same codes. Replaced MAF, and all 4 O2 sensors with genuine Bosch, still have the codes. I can drive 200+ miles on the freeway before they come back, but they will come back within 5 to 10 miles of city driving. I was about to order an intake valley pan gasket and try that, but your post has me wondering about my brakes as a (partial?) cause. They were getting pretty warn down, so had them replaced, new pads and rotors front and rear. Since then, I have had a few occasions where it almost felt like I was losing the power brakes when I had to step on them hard. (I have a '46 *****'s CJ2A, so I know what that feels like.) Were you experiencing similar issues with your brakes or something different? Also, now they feel like they need bled really bad, even though they didn't before the new brakes were put on.
Thanks for any help from your experience. I still might have to do the valley pan gasket, because when I spray starter fluid on the top rear of the engine, it clearly is sucking it in, and smooths out the rough idle. But if you had symptoms similar to mine and same codes, I might need to do the brake booster as well?

 

vacuum leaks will cause those codes and symptoms

 

Thanks, I just can't seem to find out where the leak is, unless it's the intake valley pan gasket, which seems possible given the starter fluid trick revs it when I spray it behind the alternator, or up top behind the rear of the intake / engine. Anywhere else I should look?

 

trace the big hard plastic vacuum line going to the booster iirc it heads to the back side of the intake manifold