Stalling randomly

Tiny
05PONTIACGUYL
  • MEMBER
  • 2005 PONTIAC GRAND PRIX
  • 3.6L
  • V6
  • TURBO
  • 2WD
  • AUTOMATIC
  • 110,000 MILES
I can drive my car fine after it's sat for a few hours, so I can drive it to work and to school because I get there and it sits for hours until I can leave, but If say I go to a grocery store, I get there, shut it off for 10 minutes while I shop, go outside turn it on, I get half way down a road and it stalls. I go to crank it over again, it doesn't start unless I wait 2 minutes, then it will start again. I can drive it halfway down the road and it stalls out again. When it stalls it drops to 500 RPMs, runs super rough can't move, if I press the gas pedal while its doing that it fully stalls. Fuel fuse is fine, had some corrosion I cleaned it off, may or may not be the problem going to clean it further later. Fuel pump has the normal buzz to it, I just need to get ideas of what the problem could be.
Sunday, May 8th, 2022 AT 7:05 PM

3 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 43,057 POSTS
It still can be the fuel pump but can I ask if the check engine light is on? I have seen the crankshaft angle sensor cause this issue as well. If it is a bad crankshaft sensor it will not show a trouble code or trigger a check engine light. Here is a guide to help us see what's going on with how to change out the crankshaft sensor in the diagrams below.

CKP SYSTEM VARIATION LEARN PROCEDURE
1. Install a scan tool.
2. Monitor the powertrain control module (PCM) for DTCs with a scan tool. If other DTCs are set, except DTC P0315, refer to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information for the applicable DTC.
3. Select the crankshaft position variation learn procedure with a scan tool.
4. The scan tool instructs you to perform the following:
1. Accelerate to wide open throttle (WOT).
2. Release the throttle when fuel cut-off occurs.
3. Observe the fuel cut-off specifications for the applicable engine.
4. The engine should not accelerate beyond the calibrated RPM value.
5. Release the throttle immediately if the value is exceeded.
6. Block the drive wheels.
7. Set the parking brake.
8. DO NOT apply the brake pedal.
9. Cycle the ignition from OFF to ON.
10. Apply and hold the brake pedal.
11. Start and idle the engine.
12. Turn the A/C OFF.
13. The vehicle must remain in Park or Neutral.
14. The scan tool monitors certain component signals to determine if all the conditions are met to continue with the procedure. The scan tool only displays the condition that inhibits the procedure. The scan tool monitors the following components:
- Crankshaft position (CKP) sensors activity-If there is a CKP sensor condition, refer to the applicable DTC.
- Camshaft position (CMP) signal activity-If there is a CMP signal condition, refer to the applicable DTC.
- Engine coolant temperature (ECT)-If the engine coolant temperature is not warm enough, idle the engine until the engine coolant temperature reaches the correct temperature.
5. Enable the crankshaft position system variation learn procedure with the scan tool and perform the following:
1. Accelerate to WOT.

IMPORTANT: While the learn procedure is in progress, release the throttle immediately when the engine starts to decelerate. The engine control is returned to the operator and the engine responds to throttle position after the learn procedure is complete.

2. Release when fuel cut-off occurs.
3. Test in progress.
6. The scan tool displays Learn Status: Learned this ignition. If the scan tool indicates that DTC P0315 ran and passed, the CKP variation learn procedure is complete. If the scan tool indicates DTC P0315 failed or did not run, refer to DTC P0315. If any other DTCs set, refer to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information for the applicable DTC.
7. Turn OFF the ignition for 30 seconds after the learn procedure is completed successfully.

The CKP system variation learn procedure is also required when the following service procedures have been performed, regardless of whether DTC P0315 is set.
- Engine replacement
- PCM replacement
- A harmonic balancer replacement
- Crankshaft replacement
- CKP sensor replacement
- Any engine repairs which disturb the crankshaft to CKP sensor relationship.

Also we should check the fuel pump pressure this guide can show you how.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Check out the diagrams (Below). Let us know what happens and please upload pictures or videos of the problem.
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Monday, May 9th, 2022 AT 11:07 AM
Tiny
05PONTIACGUYL
  • MEMBER
  • 2 POSTS
Hey, so. I believe I found the issue or maybe I'm lucky it hasn't happened in a few days?
I saw corrosion on my fuse box, the bottom quarter of the fuse box had corrosion and that consists of where the fuel pump fuse and relays are, I just bought a new relay because my A/C one was missing and put the brand new relay into the fuel pump relay spot, and put a brand new 15 amp fuse into the fuse spot and the problem has not happened since. So, I think it may have been a faulty relay. If it does happen again I guess I know what to try! Thank you
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Sunday, May 15th, 2022 AT 7:30 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 43,057 POSTS
Yes, a high resistance connection can cause random stalling. Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help.
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Tuesday, May 17th, 2022 AT 10:02 AM

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