[Shotimes] My '93 SHO is stalling, mechanic says idle motor (?) is issue

[Aaron Lowe]

Thanks to everyone who offered advice for my overheating problem I was 
having a couple of weeks back.  I am a little more informed now, and I want 
to bring this situation back to the SHOtimes crew, where I hope someone 
will have some good ideas.

In October, I bought a 93 SHO from a dealer I trust at a small local used 
car lot.  I was in a pinch -- my previous car had been totalled, and I 
needed transportation.  I am not really much of a car person, but I liked 
the body style of the SHO, and upon visual inspection, both the body and 
everything under the hood seemed to be in very good condition for a car 11+ 
years old.  My test drive sealed the deal for me -- having owned a 
4-cylinder VW Jetta before, the power and smoothness of handling were 
impressive.  My SHO has 130k miles, and I really don't know much about its 
history before I came to own it.

For the first 2-3 weeks I owned the car, it ran fine.  I commute 6 days a 
week about 50 highway miles each way.  Then, with no warning, the car 
started stalling when I would pull off the highway.  It ran fine for the 
whole 50 mile trip, but when I got to my exit and slowed the car down, it 
would stall at a speed of somewhere between 15 and 35 MPH.  All I had to do 
was to shift the car out of gear and turn the ignition, and it would start 
right back up.

I took the car to a mechanic I trust, and they determined that the problem 
was due to a MAF sensor malfunction.  They cleaned the MAF sensor and 
replaced a vacuum hose that they found with a hole in it.  My stalling 
problem did seem to go away.  However, within another week or so, I was 
having a new problem -- the overheating problem I wrote to this list about 
a few weeks back.

After driving a relatively short distance (5 miles or so in-town driving), 
the engine was getting extremely hot.  Now, before I started having this 
problem, the temp gauge on my dash would show my engine slowly heating up 
to normal operating temperature, and then would stay in one position -- 
between the "O" and "R" in "NORMAL."  Once I started having this 
overheating problem, the needle on the gauge was varying from the O all the 
way up to the A.  It still never left the "normal" range, but the engine 
smelled very hot and on one occasion, after driving 5 miles or so and then 
stopping in a parking lot, a few wisps of white smoke came up from under 
the hood.

So I took my SHO back to my mechanic.  They kept it for a few hours, then 
called me to tell me that yes, it was running too hot, and that the problem 
was likely the themostat.  I gave them the OK to replace the thermostat, 
which they did.

When I first picked up the car after the thermostat had been replaced, I 
was alarmed by the fact that the dashboard temp gauge continued to show 
large fluctuations that I was not used to seeing.  Again, the needle moves 
from the A, sometimes up as high as the L in normal, and then back 
again.  It moves around a lot when I am driving.  Before having this 
problem and having the thermostat replaced, I never used to visibly see the 
needle move at all.  Now I can watch it jump all over the place, and I 
don't understand this and worry that it is an indication that something is 
still wrong.

And now I am having a new stalling problem.  I can't figure out any way to 
predict when it is going to happen, other than it usually happens at lower 
speeds when I am not accelerating at all -- when I'm just "coasting" or 
braking to a stop.  The oil pressure indicator flashes red a couple of 
times, then the check engine light comes on and the car loses 
power.  Again, I can usually put it into neutral and then start it right 
back up.

My mechanic did a diagnostic on the car and tells me that the problem I'm 
having now is related to some kind of motor that controls the idle 
speed.  He says that the engine is idling too low, which is causing the 
stalling problem I'm having.  He has recommended replacing this "idle 
motor" (?), for which he has given me an out-the-door price of about $170, 
parts and labor.

Opinions, anyone?  Does this sound like a reasonable diagnosis?  I like 
this car, but I can't afford to keep sinking money into it, only to have 
more problems.

Thanks in advance,
Aaron