I know little about 95s.  Symptoms sound like it could be a vacuum leak of some sort.  Vacuum leaks can cause it to run lean which results in hot cylinders which could cause pinging and erratic idle.

 

Check all the hoses, throttle body and anything attached to the intake manifold for leaks.  The clean way is to use propane. NOT lots of propane but a little propane torch with the valve cracked open but not lit.  The dirty way is carb cleaner or the like.  When you hit a leak the idle will smooth out, and when you stop spraying it'll get rough again. go around all the seams where gaskets are and mounting bolts etc.  When you check hoses the smallest crack will cause a vacuum leak.

 

Since there are no codes or check engine light I'd almost bet there's a leak.  A misfire won't generally cause pinging as the misfiring cylinder would be wet with fuel and cool.

 

Good luck

Steve

1. It starts right up with no issue at all.

2. It's not just a rough idle - it's a rough ride in general, just moreso at idle.  And I mean, car-shaking rough, not just "lopey."  

3.  This came on very, very suddenly.  In the morning, it ran like a champ.  Not a hint of problem.  That very afternoon, I started it up and it immediately was rough, even though it started right up.  

4.  There is a "rich" smell when running the car - like too much fuel in the mix.

Would vacuum leak still be a likely possibility under all of these circumstances?  I've not dealt with one before.

Thanks.

 

I too wonder what's going on as an engine running rich usually won't ping.  Break out the shop manual I guess.  Something is going on that's not good.  You might do a sniff check of the oil to see if fuel is getting in there.  Could indicate an injector hanging open.

 

 

Another possibility is an EGR valve that is stuck open.

Unfortunately, the most common cause for symptoms like these is a problem with the Opti-Spark, or the ignition module. An ignition problem can rear it's ugly head at any given moment, with no notice.

Just because the Check Engine light is not on doesn't mean it has not set any codes. I would have it scanned while it is running....once you turn the key off, any soft codes will be gone.

Steve, took a whiff of the oil.  I felt I detected some fuel scent, but my husband doesn't think so.  Well, there you have it LOL.