I picked this car up for $600 in a pinch (in the winter of course, and it's a convertible), and it was a great runner aside from a leaking tranny and small slip occasionally going from 2nd to 3rd (like not bad at all yet). I drove it about six months before the timing belt snapped. I must say VERY occasionally it would die at idle like it is now, but it never lacked for power.

So it sat for like 9 months, I ended up draining the tank for my other car (yes I ran the starter to pump out last of gas BAD me!), but then I fixed the belt and it seemed to run fine once I cleaned the corrosion from the battery terminals, but then it just will die at idle periodically and feel like it lost most of it's spark (or more likely fuel pressure drops too much IMO), but then it comes back, like msot of the time it runs fine, then it wants to die and has no power for a second or two, then power comes back. If you goose the gas when it happens you can usually get it not to die before power comes back.

I know for sure the timing marks are right; when it is running it has all the power it ever did, just periodic losses of power and stalls, no check engine light even. I wonder if a code reader would tell anything? I don't have access to one, but I begin to think such a purchase when I can afford it would be worthwhile, but if no engine light, would it matter here?

My guess is it is a fuel pressure drop. The system seems simple and I put everything back as it was after getting the gas all out, but perhaps a faulty component (filter, pressure regulator, MAF, ?!?), though I suppose water in the electrics is possible (Washington state, high humidity and lots of rain, and it has sat with hood open), but I have no code scanner (May buy one next month though). No check engine light ever came on though, so I suspect a code scanner, especially considering that it's the older less reliable OBD1, may not solve the mystery anyway.

IDK if it's important, or any different from a proper 323, but with the Mercury, the fuel filter is in the engine bay (THANK GOD), rather than the fuel tank, so I can't afford a new one today, but it's an EASY fix. I tried some Heet in the gas, that didn't help.

Sorry for the long post, but this car is quite rare, and finding Mercury enthusiasts on slow moving Mercury boards to answer questions has been thus far fruitless. It is essentially a Mazda 323's DOHC 1.6l with an Auto tranny, no Turbo, sold under Ford as a Mercury. Any help is appreciated, thanks!

 

I hope you found your answers somewhere, maybe on the Mazda forum. There is a rather complete unofficial user guide to the Mazda Protege (same as 323). I bet your air intake hose was deteriorated.

 

If you can, see if your auto supplier can get you a little tool made by THEXTON #443. It comes with instructions and works very well for OBD I on Ford Products I believe it runs for approx, $25.00 .Great tool and does the job. There are some fantastic things Ford OBD I does for you with this tool.
Provides "Hard codes"
Continuious codes
And does Dynamic Testing ,all, automatically (Built into the ECA)
If you get it , I can assist you in getting the most out of it.