Bad Idle and cut off at stop

Hello folks This is Richard and I have a 94 Stealth RT (NA) here in Md USA. I’m having an issue with my idle. During a cold start the idle will rev to 2000k rpm’s, then after a a short period it will level to around 1200k. If I leave it running without moving the car, when it reaches operating temp it will start sputtering and then cut on. I have change the valve cover gaskets (via Joe’s video), removed the throttle body and replace that gasket, replaced the Idle Air Control, replaced the Throttle Position Sensor and calibrated via the repair manual. Cleaned the MAF first with Carb cleaner, then with MASS AIR CLEANER. Now when I come to a stop it will cut off also. I think it will keep running if I have the AC on, but still gasps for air or fuel. I’m a bit lost and out of ideas other than buying a new MAF. If anybody could tell me what I’m missing or have done incorrect I’d greatly appreciate it. BTW, it runs fantastic at almost 100mph in 3 gear and hit 110 in fourth before I’d had enough.
Thanks any and everybody that could help

Hi Richard,

This sounds strikingly similar to an issue I was battling for a few months, documented in this thread:

My issue was stalling when idling at operating temp, or when changing gears (auto trans). Turning the AC on would usually prevent it from stalling, but it would always bog a little.
My fix was raising the idle a few hundred rpm, but I don’t think that was the root cause, only a masking solution.

Since you have a 94, I believe you should have an OBD2 port.
If so, I would highly recommend purchasing an OBD2 to USB cable (can be found on amazon for pretty cheap) and connecting your car to a laptop so that you can monitor real-time data.
This will give you some more insight as to what exactly could be causing the problem and who knows, might point me towards the root cause of my issue lol.

Please do keep this thread updated with your findings!


Thanks Cristian, think you could point me to a good download for the laptop?

When you changed parts,did you then perform the base idle settings procedure as per manual
Sounds like the ECU doesn’t know what’s going on

Thanks Steve for your reply. Unfortunately I didn’t, guess I was so excited about my new parts going in and the engine paint going on that I didn’t realize that I needed to. Is there a procedure for each part ie TPS, IAC or are there different methods for each part? Guess I thought I could just change them like it is a 70’s hoopty.

Hey sorry for the delayed response here,

ScanTool OBDLink SX USB:…

Something like this would probably work fine, I’ve used the software that cord come with on a different car and if I remember correctly it should display all the data you will need.

OBD2 is standard, so I think any OBD2 Live Data Monitoring software should do the trick.

Let me know if this helps.


Also I just realized that you said you cleaned your MAF.
I was under the impression that this is fine but I have been told otherwise by some people on reddit who say that the stock MAF shouldn’t be cleaned with standard carb or maf cleaner. So I’m not too sure about this but your MAF could very well be the issue, just thought I’d mention it.

There you go