i am happy to tell you i too used MMO and it worked very well. I had a stuck lifter and it was realllly annoying. I thought it was an exhaust leak at first. Two treatments of the MMO stuff. one quart per oil change and the noise is gone. Now i can hear everything else that makes noise.
sure cleaned out the motor and got the plumbing cleared up i'd imagine.
then i added some to my gas and now my fuel pump spins up nice and smooth instead of stuttering when i first turn key.
that MMO crap is good stuff. that is if you use it before problems get bad.
the first oil change i did and added a quart, my oil got dark pretty fast as it the engine was being cleaned of gunk. replace filter too. do this a couple of times.
i will use one quart per oil change for the next few changes i do and then leave it be.
benefits: smoother quieter engine, no more loud ticks, of course some ticking is normal, easier starts. that itself is worth the money to buy a 4.25 quart of MMO.
if you need repairs do them though, this is just to clear up small quirks.
i was a bit nervous to do the ATF cleaning method so I chose MMO. on the cotton farm my inlaws used it for years to get old tractors running. they told me that they had kept this MMO secret from asians like me for years but it was time to break me in. YOWWW!!!