Intermittent Stumble and Stall

[theKnifeArtist]

So this has been occuring not too long ago out of the blue. When comming to a stop and dropping the RPMs (not even abruptly), the car will go into a low rpm idle where it will feel like its missing or something, even with a little help with some gas trying to even it out.
This happens randomly. Today it did it most of the day. Before that it didn't do it for a while. Before that it would do it like twice a day.

My codes are:
12-RPM Signal (Code stored when car turns out without an ignition signal?)
34-Turbocharger Pressure (Not Related:dunno
41-Throttle Position Sensor Signal (Could be related)

If the TPS wasnt adjusted right, the code would come right back up after clearing right? Cus they all clear. Tommorrow I'll drive the car after clearing it and see what occurs.


Here's the kicker
I had all these codes in before I had this issue.

Any ideas?

 

[jdub]

Code 12 is: "No NE or G signal to the ECU within 2 sec after engine crank".
That means the CPS or it's wiring...could be the STA signal as well.

Code 41 is: "Open or short circuit in TPS signal".
That means the TPS itself or it's circuit...nothing to do with adjusting the TPS.

Both (NE and TPS) are inputs to the ECU idle speed control

Sounds like you might want to grab a multimeter and start checking circuits...I would start by checking the connectors to the CPS and TPS.

 

[metaphysico]

The tps tells the computer the load of the engine. Very easy and quick to test.

 

[jdub]

The tps tells the computer the load of the engine. Very easy and quick to test.

Ummmm...no :3d_frown:

The TPS does two things:
- Informs the ECU if the car is at idle (IDL on/off)
- Informs the ECU of throttle plate position (VTA signal)

The TPS tells the ECU nothing (at all) about engine load.

You're new, so you need to know. This is the Tech Section...if you are not 100% sure of what you're saying, do not post.

 

[ForcedTorque]

I bought a 1 year old very good wiring harness, and all my codes went away just like I pulled the EFI fuse. They were very similar to yours.

For the life of me, I can't figure out why they would explain codes with a Greek lettering system like they do. Where do they get VTA out of Throttle Plate Position?

 

[Supra87T]

I bought a 1 year old very good wiring harness, and all my codes went away just like I pulled the EFI fuse. They were very similar to yours.

For the life of me, I can't figure out why they would explain codes with a Greek lettering system like they do. Where do they get VTA out of Throttle Plate Position?

VTA = Variable Throttle Angle

Not necessarily Greek

 

[billwert]

I had a problem similar to this. It turned out to be my TPS. Jdub was very helpful in assisting me.

 

[theKnifeArtist]

yeah i've seen similars issues pointing to TPS, but i'm gonna go ahead and check connections at the cps and tps like jdub said