I have gotten a check engine light recently and when not in gear just idling the car sometimes revs all the way to 1800 or twitters up and down between 600 - 900 I had Autozone check the error code with their computer and it came up with it being a problem with the TPS so I replaced the sensor and still get the problem checked it again and it still said it was the TPS so I checked all the grounds that I could see on the engine to make sure it wasn't a grounding problem and I am still getting the error. The check engine light is no longer on but the revving and twittering is still occurring what could be the issue?

 

please post actual code number and we'll take it from there

 

The problem is the check engine light is no longer on and the code doesn't appear, but the same problem is still occurring I can try and find out what the code was for you in the next couple of days

 

Not even stored as a "pending" code?

 

I will go and have it checked again and get back to you.

 

Rather than start a new thread, I thought I would tack my issue into this one and see if anyone had suggestions. I will explain the issue and then state what I have done to try to fix it, as best I can recall.
First, I have a 1995 SC2, manual trans. Second, the idle problem is very similar to what Chaos describes. If the car is cold, there are no issues, but once it reaches normal operating temp, it starts doing this: reving up to nearly 2000 and then droping back down below 1000 and frequently stalling. Once stalled, the only way to start it is to press the gas pedal to the floor and hold it there while starting. If I leave the pedal on the floor, it often coughs and sputters (once started) as if it's not getting enough gas to run and finally "realizes" that it's getting more than enough gas and begins to rev up just like it should. I have to let off the gas to let the RPM's drop off. If I take my foot totally off the gas, it will start the cycle over. While doing this reving/stalling cycle, if I press on the pedal while it's still running, instead of increasing the idle speed, it acts like I have just cut off the gas supply and starts coughing and sputtering. After tapping the gas pedal a number of times it seems to "realize" that I'm actually trying to keep it running. This is a real pain in city traffic because it stalls on me at least once during every stop light.

What I have done (basically in order) to try to fix this issue:
1) Replaced oxygen sensor (New) (Suggested by someone who doesn't know Saturns, but knew other vehicles).
2) Replaced Idle Air Control valve (new)
3) Replaced EGR valve (used)
4) Replaced Ignition switch (New)
4) Replaced fuel pump (used)
5) Replaced Power Control Module (used)

And the issue has never gone away nor improved during all of these replacements. Any suggestions?


Thanks.

 

0) SES light on? If so, any codes?
1) How many miles on the car?
2) Have you ever replaced ECTS with brass style replacement? If not, replace ECTS and connector.
3) Did you clean the used EGR valve before installing to ensure free pintle movement?
4) Did you clean the ports where the EGR attaches?

I would ask if you checked for vacuum leaks but since you said it's fine until it gets warmed up, I'll forgo that.

I have a hunch (EGR) but I'll wait for the responses to the above before delving into that...

 

Hey Derf --

My guess is for the ECTS, or a bad connection going to it. Fits perfectly with the problem of the system not recognizing the engine is up to operating temperatures, and the PCM won't adjust the air/fuel accordingly. we shall see .....

 

At the moment, no codes. I just recently re-connected the battery after it had been sitting for a while waiting for parts, so all codes (if present) would have been cleared.
Approx 138k miles.
When I first got the car a few years back, the radiator fan would not kick in. After some checking, I replaced the top sensor but didn't know there was a lower one. Then I replaced the second one and that fixed the fan issue. I will check, however, to make sure the connectors are in good shape and get back to you on that.
While I don't recall specifically cleaning the EGR and ports, I most likely did since I do remember cleaning the throttle body before putting the new AIC valve on. I will, however check this as well and clean it as needed.

Thanks again.

 

OA,

Normally I would say the same thing, but the oscillating RPMS and the stalling on decel followed by "nearly impossible to start" in my experience has been EGR clogging....

Indeed we shall see if an ECTS swap cures all.....