Hi
We bought our Moen (Chateau) faucet two years ago, partially because of the name brand and partially because it was the only one that we could find with a side sprayer and that would hook up to our newly purchased portable dishwasher.

Now the whole faucet is completely loose, one part will tighten for a while and then become loose again and another part will not budge. We cannot tighten or loosen the screw or even take the part off if we could replace it. Once it gets really loose water starts to pour out from where the spout meeting the mounting plate.

I have contacted Moen and they advise that none of their faucets are made to be used with a portable dishwasher. That this voids their warranty and they want pictures to determine the part that is not working. I have explained that it's the whole thing that is completely loose, including the spout/faucet and the mounting plate. We have been able to tighten the plate, but every time we swivel the faucet from one sink to the other, if gets looser.

I have been searching online and in stores for months for a faucet that can be used. We need a 4 hole faucet preferably with a side sprayer. We would prefer to have an high arc as well. I have purchased 2 or 3 that looked right in the store, but didn't work and they had to be returned.
This is getting urgent (and annoying)
Any suggestions or ideas?
We also cannot afford to be spending more than a couple hundred dollars on it.

One of my "customers" recently called with the same problem. The problem is not the use of the portable dishwasher but the stress that is put on the spout when connecting and disconnecting the dishwasher.
The spout assembly, the working part that in inside the spout, is attached to the escutcheon plate with two 4-40 screws. The escutcheon plate is thin, soft metal and not capable of sustaining stress put on the spout when repeatedly connecting and disconnecting. The two screws had pulled through the escutcheon plate.
I did a temporary fix by replacing the two 4-40 screws with longer screws and add a washer to each screw.

At some time in the future, probably in the next week or so, I intend to return and do a more permanent fix. I will drill out the 4-40 screw holes and re-thread to a #6 or #8 screw. I will install a screw long enough to reach to beneath the sink rim (it is a stainless steel sink). I will then cut off the head of the screw, pass the screw through the escutcheon and secure it with a nut. I will then reinstall the faucet on the sink.

I will then cut a bracket about 2" long from 1/2" wide flat steel and drill a hole in the center. I will put a bracket like this on each screw from underneath the sink and secure it with a nut.

After doing this the spout assembly will be bolted to the sink flange, not just the escutcheon plate.

I don't think she will be able to break that.

Maybe you should consider the same approach.

one part will tighten for a while and then become loose again and another part will not budgeWhat parts are you trying to tighter? The mounting bolts on the bottom? Do you have a basin wrench (see image) to tighten the bolts? As I understand it you have cobbled up a way to connect your DW to the spray hose. How long did that last and what went wrong? I don't have enough Information to answer your question and if fact I'm not too sure about what you're attempting to do. Repair the old faucet or locate a new one. Help me out here. Back to you, Tom

the hardware bracket that secrures the spout/faucet to the plate, one screw turns and loosens and tightens and the other one will not budge.

Moen agreed to send out the hardware bracket to us free as part of the warranty now, but I don't think we'll even be able to get the old one off to replace it?

http://www.moen.ca/replacement-parts/search?context=partorModelNumber&value=7430

is the page and I believe its part 93959 at the bottom of the first picture
Hopefully the part they send works

Part 93959 is on second page. Could you mean 146790 (on first page)?