I typed in a long reply and then hit submit. I got a message saying that my reply had to be greater than five characters! Grrrrrr! I hate saying the same thing more than once, I hate having to type it twice even more! At this point, I have tried to post 10 or 15 times now, this is REALLY agrivating.

First, the actual mileage is just over 139k. Not a huge difference, but a difference none-the-less.
I checked the connectors on both temperature sensors and they look good (no corrosion).
I took the EGR valve off and cleaned the pintle and the port on it as well as the two ports on the engine. The pintle seemed to move freely before I cleaned it, however, it did have a fair amount of carbon on it. I replaced it and started the car. I let it run for about 10 - 15 minutes and the idle speed did vary a little bit, but it seemed to want to stay around 900 (a little lower than before). When I pressed on the gas pedal, it didn't act like I cut off the gas flow like it did before. I drove it around the block twice and while idling at stop signs, didn't have the reving issue and as I said before, I could step on the gas and get reving instead of coughing and sputtering. I can't test it much more than this until I renew the tags on Wednesday. While waiting for parts, the tags expired and since he wasn't road safe, I didn't worry about the tags. Once I get the tags legal, I will put him through a more rigorous test and post the results here.

Hope this helps others.

 

I have had a similar problem on my 95 SC2 as well, mine ended up being the TPS (Throttle Positioning Sensor) take it to you local mechanic and just show him and see what he thinks, cost me 50 bucks to have my mechanic do it for me, try that and let me know, im curious.

 

OK, sorry for the really long time between posts, but I have been dealing with some more pressing (non-automotive) issues. When I first read this reply, I looked in my Haynes manual and saw nothing listed under TPS or Throttle Position Sensor in the index . Recently, while reading the section about the Throttle Body, I found the TPS removal and installation passage! I am not in a position to take any of my vehicles to a mechanic, so I do almost all the work myself.

I also checked the error codes stored in the PCM and have these three:
15
24
26
I have already done my research and know that these refer to "Coolant sensor/low Temp, VSS Circuit - no signal," and "Quad driver output fault."

Both the Temperature Sending Unit and the Engine Coolant Temperature sensor where replaced when I got the car a few years ago. They both still look new, however, I'm having a little issue checking the voltage going to the ECTS since the harness has such small holes, most multi-meters don't have contacts that size. I also have the same issue trying to check the resistance on the sensor itself.

While driving at highway speeds using the cruise control, when I signal to change lanes, the speedometer drops to zero momentarily and then swings back up to the correct numbers. I figure that is why the VSS Circuit code is coming up. I don't know if that means I need to replace the VSS or not?

As for the Quad Drive output fault, I know it could be one or more of these 8 items:
1) SES light burned out (obviously working since I got my codes)
2) "HOT" light burned out (shows up when I turn the car on)
3) A/C relay (not sure exactly how to check this)
4) Coolant fan relay (also not sure how to check)
5) EGR solenoid (my EGR doesn't appear to have a separate solenoid)
6) Canister purge solenoid (haven't checked/removed this item yet)
7) Speedometer output (VSS issue again?)
8) Upshift/Shift to D2 bulb (bulb is fine as it shows up at start up and when I need to shift)

The TPS has its own error code and that one is not stored, so I'm going to guess that is working properly.

Also suggested was the fuel filter. Would that cause intermittent idle problems and only when hot?

So that's where I've gotten to thus far.

 

Interesting development! Just before going on a trip from Northwestern Ohio to Southwestern Michigan, I checked both the Temperature Sending Unit and the Coolant Temperature Sensor. Both looked great, but the connectors looked dirty, so I put some di-electric grease on the connectors before hooking them up again. During this trip, I had none of the idling problems I have been having for the past several years! I even had a jump in gas mileage! So, I think this means problem solved!

Thanks for the guidance.

 

That's why we always suggest to replace the connector along with the ECTS (see post above) -- two little contacts + corrosion = whole lotta problems...

So it sounds like a combo of ECTS swap + connector contacts and EGR cleaning have put you back on the path to Saturn enjoyment.

Motor on......