Hi,

I thought I would talk about your car for awhile. Nothing else better to do or really wanting to do, is more likely it! (:-) I got that old lazy-I-is diease again! A little Rain is coming in helps too,

From the way you describe how you are keeping it running and it will keep running makes me Quote or Copy, a line from one of (one pocket aka: trichard) earlier posts.
2. anytime an engine is running however badly and sputters and act to try and keep running running but eventually dies look for fuel problem.

I whole heartedly agree with his "overall" two part assessment of how an engine can run!

You mention about the car sitting for "a couple months" and I want to expand that accessment a little bit.
1. Are you sure it was only a couple months? Time slips aways fast for me.
2. How empty was the gas tank when parked?

I ask, as the amount of air, sitting above the gas in the tank, affects the oxidation rates of the gas along with its evaporation.
In other words,the gas rots or goes bad quicker if not in a sealed container with little air.
It also loses octane value and if you are using 87 or less than the recommended 89 fuel you are working with nearly nothing but paint thinner.
Todays fuel absorbs moisture, especially with ethanol in it and if left long enough, it helps begin to congeal leaving gum on things.
If that has happen, You need fresher fuel and one with Tier 2 detergents to help clean up the fuel system. Fresh gas will dilute or thin out old fuel if it's not too bad.

It seems to me that it's possible, that the spray patterns out of the injectors, are not completely conical in order to get a clean combustion in the cylinders.
One would think it's running with too much of a rich mixture.
You add pedal, of which, adds air and not gas, to the cylinders. Thus, this does help spread the lumpy amounts of fuel to get mixed up.
As the engine gets warmer, things get easier to vaporize and it runs better.

The thing about the engine taking 15 minutes to get up to temperature is a bit long unless it's really cold. You might have a thermostat stuck open or one that is not 92 degrees centigrade.
I only trust WAHLER brand thermostats to do the job right the longest!

The engine is suppose to go close loop with the oxygen sensor long before then.
The system uses that information to run the engine in the warming up mode and then finally in the fully hot mode of the ECU program!

This is why, Mr. One Pocket, is questioning the oxygen sensor signal!
The ceramic heater is there, for these particular car years of ... LH 2.2 & 2.4's and 3.1 in some of the 1993's!
The sensors job is to help hurry this along, some what, but it really only takes a minute or so, for those flames to heat it up for the older cars emissions days. That's when they were at the base of the exhaust manifold.
Only trouble is, on these cars, that's even are farther away down into the catalyst converter.
Since your engine is not burning fuel well, it's leaving you hanging the foot on the pedal!
The cars engine should and can do everything without you even in the seat!

For years, My test was reaching through the window and see if I'm still nimble enough to reach the key, to twist it!
Now, It's getting where I open the door and lean over to reach my manual transmissions shifters!
I questioned my eyesight and my stooping angles looking through the window opening.
I need to feel the neutrals slack position.
This Getting old thing, is not for sissies!

The IAC should rev it up past normal idle and bring it back down to a 750 rpm!
If not, there is a problem with its internal action or another outside source of air messing with the AMM's calculations.

From what you say that's doing ok after its all warmed up?
You said, after it runs up to normal temperatures, it's running fine, but then, you know it's really not!
But you'll take it!
That means no check engine light too! Right!
You got to share these things with us!

Also when was the last ignition tuneup done?
Bad sparks and lame fuel octane spells trouble!

Get those two things up to par and squared away, then you and us, will know what we are dealing with!

Phil