Fast Idle When Warm
 

Had a weird occurrence yesterday. While I was checking out an AMC Marlin at a dealer lot, I left my SC running, idling. When I get back, I see that it's running at 2k rpm and the temp gauge is at half and turning on the fan. I blipped the throttle to see if it would kick back down to normal, but it didn't do anything. That ended the enjoyable cruise out last night. Coming home with airflow into the radiator, the temp came down to normal. After parking, turning off and turning back on the engine, it returned to the normal 800-ish rpm idle.

I don't seem to recall when that high idle started, but the engine was at operating temperature. I only noticed the high rpm after it had sat idling for a couple minutes. I did replace the Throttle Position Sensor recently. Did I screw that up somehow?

Coolant still gurgles into the heater core like an upstairs toilet raining down it's goodness, but I've checked on it for a while and I'm not losing any. Tank is where it needs to be and the pavement is dry under the car.

THrottle plate sticking?
ECTS and connector replaced?
The fact that restart cured issue makes me lean towards TPS.

did you use cheesy AutoBlown TPS as a replacement? Charlie used to work there and said their electronics based parts were crap. I consider NAPA a step up. I consider RockAuto.com a good place to buy parts as long as you stay away from the lowest priced replacement for your device, as they always seem to be the most expensive of the crappiest, offered to the consumer who won't pay the extra $5.00 for a quality part.

I would price out OEM GM repl part vs AC Delco and maybe Standard on RockAuto. I have read too many reviews of Airtex parts to ever buy one. I've bought a few Standard parts and not had issues. Would like to know others' experiences.

Obv, OEM is preferable if reasonably priced. AC Declo should be identical part #. Don't know about the gasket thing (RockAuto AC Delco)

Got the sensor at Advanced. I'll keep an eye on it and see if the issue returns. If nothing else, I saved the original one and I can put that back in. A misdiagnosis of a problem led me to change it. There has been no light on the dash alerting me to a problem.

New symptom today: retarded acceleration!

Had to run to the nearest big city today. Trip was a 30 minute highway jaunt both ways. Get off the highway and try to accelerate from the offramp to the local roads. Car says nope! Very sluggish acceleration. I floored the pedal and it felt like I was only getting 1/8 power. Also, temp went up to just before the fans kick in. It was a hot day today and I had been running the A/C, so the transition from moving to sitting might account for that. Coming back on the highway, the car gave almost no passing power at speed. Cruising at a constant speed was just fine though.

Coming off the highway, same symptoms: No power. Barely accelerating. Ok at a set speed.

I'm thinking I'll be looking at the throttle body again this week.

Yah, you need to get your electrical parts at a dealer or NAPA. I have worked for both Autozone and Advance and both of their electrical parts are sub-standard. I don't buy mine from either place. They're usually second quality parts and they are NOT properly calibrated for all of the cars that they'll fit. It's best to use OEM parts on your Saturn instead of aftermarket when it comes to the electrical stuff. Put the old TPS back on it and I'm guessing it'll do better than what it's doing now.

So I've put the original TPS back into the throttle body. The throttle valve is clean as a whistle. Took it for a drive in urban, highway, and rural roads. No strange idles, good throttle response, passing power is there whenever I need it. I'll keep an eye on it, but I'd say it's fixed.


Looking at the box...Made in Taiwan. I'm sure they make lots of quality things in Taiwan, but throttle position sensors aren't one of them. If you get handed a box like this, hand it back!