1988 Oldsmobile 2.5L TBI 192,000 mi, Stalling, Runs Rich?

I am sick of this problem with my car. It has gradually gotten worse
over the past few months. I don't know if all the events are related,
but here they are.

It started with the cruise control just turning off for no apparent
reason going down the highway. That happened a few times over a few
weeks (my highway trips are on the weekends). Then, going down the
highway, it seemed to shift into the wrong gear, (it's an automatic
transmission), and just stay there until it decided to jump back to the
"correct" gear, so I thought a transmission problem was developing.
After a while whenever it did that, the service engine soon light would
come on too, which I could understand, if the idle was wrong and it was
in the wrong gear, but now I don't believe it's a tranny problem. Then
one day, on the way home from church (30 mph) it started cutting out
and when I stopped at the light at the bottom of the hill, it stalled
and I couldn't get it started for 5 min or so. I just cranked it to try
to start it every 20 sec or so and when it wasn't starting, it just
cranked and cranked. But when it finally started, it started
immediately, like nothing was wrong. I knew my plugs and wires were
overdue, so I decided to change them, hoping that would correct the
problem. It didn't, so I replaced the coil for the 1-4 cylinders. That
didn't help, either. After searching online and in my Haynes manual and
in my notes from college (I have an Associates in Automotive
Technology), I started replacing sensors.
The current situation is that the car won't start unless I have my foot
on the gas (a little). If I take my foot off the gas after it's
running, it idles so low, it sounds like it's going to stall. If I go
back to the muffler and smell the exhaust, it smells rich (no black
smoke though). Sometimes when I try to start it though, it will start
and idle normally, but if I leave it running for a while, eventually it
suddenly starts to run rough, and really low, and I have noticed at the
same time, the fan turns on. Don't know if this is normal or not.
OK, so this is what I have replaced/tried, one thing at a time, so I
could determine what the cause is. Before this problem started (or
about the same time) I had to have my fuel tank replaced (last fall).
Then during an indian summer we had this winter, I replaced my fuel
filter and fuel lines (with rubber ones). Then once this problem
started getting worse, I did the plugs and wires and an oil change, new
oil filter, pcv valve, air filter, breather filter.
When that didn't work, I replaced the cyl 1-4 coil with a new one
because gap on the old plug for cyl 1 was a little wide when I pulled
it, and I heard that excessive gap could hurt a coil. That didn't solve
my problem. It still cut out randomly and stalled eventually. The cat
is relatively new, also. Had a stupid exhaust leak I was struggling
with for a while, but eventually sealed.
Enough rambling, here's the list.

plugs (new, mid-quality)
wires (new)
coil (new)
oil change
oil filter (new)
air filter & breather filter (new)
pcv valve (new)
O2 sensor (new)
EGR valve (new)
ICM (new)
MAP sensor (used)
ECT sensor (new)
Engine temp sensor (in block under thermostat, used)
thermostat (new)
injector (used)
fuel filter (new, but sat around for months before installed)
rubber fuel lines (new)
TPS (used)
crankshaft position sensor (new)

I have cleaned the IAC with carb cleaner (I suppose it could just be
defective)

If I disconnect the EGR valve vacuum line, nothing happens.
If I unplug the IAC, nothing happens.
If I disconnect the MAP, either electrically or vacuum line, nothing
happens.
If I unplug the O2S the check engine light will come on, but does not
affect idle speed.

I have jumped the A & B terminals of the computer connector, and the
only code I got was 12, which just means no distributor ref.

If I hold my foot on the gas at a low speed, the engine runs so rough
it shakes, and if I increase the fuel, the itle speed raises and the
shaking is less and I can hear a little miss or something through the
exhaust. I can't get it to reset the idle to correct speed by revving
it.

If an engine is running rich, will the idle go down? or is that
contradictory? One website I found suggested replacing the fuel
pressure regulator.

The last few items I'm thinking of replacing to try to fix this problem
before taking it to a shop and paying big bucks for something simple I
could have done myself a

Fuel pressure regulator (used) -or-
fuel pressure regulator diaphragm (new)
Engine temp sensor (new)
The other coil

The TCC solenoid was replaced a couple(?) years ago.

The radiator has a very tiny leak, it was replaced used a year or so
ago.

I replaced the alternator (used) and battery (used) this winter also
(because they died).

This has now cost me $300 (with the addition of the ICM to the list)
and I am now getting very frustrated. At first I didn't mind replacing
the sensors since the car has 192,000 miles, they were due. But now
it's getting expensive. And if I have to take it to a shop besides...

> wrote in message
oups.com...
> I am sick of this problem with my car. It has gradually gotten worse
> over the past few months. I don't know if all the events are related,
> but here they are.
>

It seems to me that your neglecting the basics. First, have you checked the
manifold
vacuum with a vacuum guage? You could have a leak. Another way to check is
to use
a propane torch and blow propane around suspected leak areas, if you get a
change in
idle speed you have a leak. And of course there will always be a slight
leak around
where the throttle linkage connects to the shaft since the shaft has to turn
freely. Second
have you checked the timing with a timing light? Granted yours is
computer-controlled but
that just means you cannot adjust it (easily) but it still can be measured.
Third have you run the thing
through an emissions testing station (most areas of the country have them
and quite a lot
of states are like Oregon, where emissions testing is free if your not
renewing your tags)
Fourth have you checked the fuel pressure in the fuel system? Fifth have
you disassembled
the throttle body and cleaned it?

It seems to me that what your doing is guessing at the problem then you
replace a part and
see if your guess was right. Your not doing any real diagnostics. And
frankly that is a shame
since your car is an 88 and a GM besides, and you can get real professional
grade OTC diagnostic
gear that will plug into the diagnostics connector and do that year of
vehicle for next to nothing off Ebay,
nowadays.

Also it seems to me that your favoring guesses that are easy to change out
over guesses that take
a lot of time and are hard to check out. Like the throttle body cleaning,
it takes a while and
some effort, compared to changing out a sensor, which you just do in 5
minutes with a wrench
and a screwdriver. That is one of the problems DIYers sometimes have, they
want to get their
car fixed right away, they don't want to spend a long messy time of it, so
they favor the easy
obvious jobs (like replacing spark plugs) over the hard complex jobs (like
reading the factory service
manual and following the troubleshooting tree)

Ted

Ted, well stated, lots of issues just like that on this forum.
"Ted Mittelstaedt" > wrote in message
...
>
> > wrote in message
> oups.com...
>> I am sick of this problem with my car. It has gradually gotten worse
>> over the past few months. I don't know if all the events are related,
>> but here they are.
>>
>
> It seems to me that your neglecting the basics. First, have you checked
> the
> manifold
> vacuum with a vacuum guage? You could have a leak. Another way to check
> is
> to use
> a propane torch and blow propane around suspected leak areas, if you get a
> change in
> idle speed you have a leak. And of course there will always be a slight
> leak around
> where the throttle linkage connects to the shaft since the shaft has to
> turn
> freely. Second
> have you checked the timing with a timing light? Granted yours is
> computer-controlled but
> that just means you cannot adjust it (easily) but it still can be
> measured.
> Third have you run the thing
> through an emissions testing station (most areas of the country have them
> and quite a lot
> of states are like Oregon, where emissions testing is free if your not
> renewing your tags)
> Fourth have you checked the fuel pressure in the fuel system? Fifth have
> you disassembled
> the throttle body and cleaned it?
>
> It seems to me that what your doing is guessing at the problem then you
> replace a part and
> see if your guess was right. Your not doing any real diagnostics. And
> frankly that is a shame
> since your car is an 88 and a GM besides, and you can get real
> professional
> grade OTC diagnostic
> gear that will plug into the diagnostics connector and do that year of
> vehicle for next to nothing off Ebay,
> nowadays.
>
> Also it seems to me that your favoring guesses that are easy to change out
> over guesses that take
> a lot of time and are hard to check out. Like the throttle body cleaning,
> it takes a while and
> some effort, compared to changing out a sensor, which you just do in 5
> minutes with a wrench
> and a screwdriver. That is one of the problems DIYers sometimes have,
> they
> want to get their
> car fixed right away, they don't want to spend a long messy time of it, so
> they favor the easy
> obvious jobs (like replacing spark plugs) over the hard complex jobs (like
> reading the factory service
> manual and following the troubleshooting tree)
>
> Ted
>
>
>



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well, i don't have gauges to check vacuum and fuel pressure, so i
didn't do that. this morning, i started it and it ran fine. i took some
starter fluid that someone gave me to find out if i had a vacuum leak
and sprayed it around and it didn't affect the idle.
i decided to take it to a shop right by my house. my boss is asking a
favor of the guy to check out my car. he's going to look at it tomorrow
to confirm, but when he asked me what the car was doing, plus a couple
leading questions, he immediately said they were indicators of the main
computer going out. which is what i originally thought, myself, since
my mom's car did this (similar symptoms) a couple years ago. but i was
mistaken in what the icm was. i thought that was what i was replacing
was the computer. silly me. the mechanic at this shop said it's behind
the right kickpanel. now i just feel like an idiot.

> wrote in message
ups.com...
> well, i don't have gauges to check vacuum and fuel pressure, so i
> didn't do that. this morning, i started it and it ran fine. i took some
> starter fluid that someone gave me to find out if i had a vacuum leak
> and sprayed it around and it didn't affect the idle.
> i decided to take it to a shop right by my house. my boss is asking a
> favor of the guy to check out my car. he's going to look at it tomorrow
> to confirm, but when he asked me what the car was doing, plus a couple
> leading questions, he immediately said they were indicators of the main
> computer going out. which is what i originally thought, myself, since
> my mom's car did this (similar symptoms) a couple years ago. but i was
> mistaken in what the icm was. i thought that was what i was replacing
> was the computer. silly me. the mechanic at this shop said it's behind
> the right kickpanel. now i just feel like an idiot.
>

I will bet you a short case that the main computer is not going out in this
car. And I said propane, not starter fluid. If there is a vacuum leak
in a hose somewhere that you spray with starter fluid only some of the
fluid will get sucked in and it will certainly wick to the side of the hose
long
before it makes it to the manifold. Not to mention spraying starter fluid
on
a running engine is a taking a chance you are going to catch the car on
fire.

Mechanics always blame the computer when they perceive that they
are talking to someone who isn't car savvy. The reason is that if your
shaky on your vehicle mechanical knowledge, you almost certainly
look at the computer as a big black box and are quite willing to
believe that something is wrong with it.

Ted