Repeated Stalling at Stops!!!

[White_Beast98]

When I get into my car and start it. It will turn over and go like a pro. But when I stop with it in drive or reverse, it will surge and stop running or it will just stop running. Some times in park it will just stop running. But each time it stalls it will start right back up like nothing is wrong. I have changed the pcv valve and cleaned the egr valve. I have also checked for vaccum leaks and also took of the intake just to see if I could find something unusual.

I read on one of the post about changing 3 sensors. Two of them being camshaft position sensors. I forget what the other was. but if anyone could give any advise please feel free.

[tjm]

sounds like it may be the mass airflow sensor - it can sometimes be bad without tripping the SES light.

is the SES light on???

[aurorabrain]

Answer....
You have a bad crank sensor. Switch plug wires 1 and 4, if that fixes it it is the upper crank sensor. If not, switch 6 and 7 and if that fixes it it is the lower crank sensor. The lower one can be changed easily on 95-99 cars but the upper one requires moving the a/c line out of the way.

[White_Beast98]

The SES light doesn't come on.

[White_Beast98]

Does anyone have the locations and the directions on how to change a camshaft position sensor???

[aurorabrain]

The SES light will not come on when you have this problem, but it will store a code for "stall, or near stall detected." I've fixed 4 of these problems, 3 auroras, 1 cadillac. I will bet any amount of money that its a crank sensor.

GM Service Information:
Condition/Concern:
Some1996-1999 Oldsmobile Aurora with the 4.0L(L47) and Cadillac vehicles with the 4.6L (LD8 L37) Northstar engine may exhibit an intermittent stall/near stall/idle flare or flux while the vehicle is at idle. The customer may not notice the near stall but, will notice the idle flare as the PCM tries to save the engine from stalling. Normally this condition will be accompanied with a PCM code P1599 for stall or near stall detected.

Recommendation/Instructions:
This condition of an intermittent slow speed decel stall may be caused by carbon deposits formed on the IAC and EGR valve or in the throttle body passages. If this vehicle stalls when coasting above speeds of 20 mph, one possible cause maybe the EGR valve sticking. (As with speeds above 20 mph the P0401 diagnostic will exercise the EGR valve to near 100% when certain conditions have been met.). The sticking condition may not be on the pintle end of the valve, but on the shaft; therefore cleaning the EGR valve may not improve this stall condition. It is important to note that the P0401 diagnostic does not seem to run when the Tech 2 is in the snapshot mode. This prevents a technician from seeing the condition as it occurs.
If the answer to either of these questions is yes, then the condition is not the EGR sticking from the P0401 diagnostic.
Does the vehicle stall when coasting with the speed below 20 mph?
Can the condition be captured on the Tech 2 or VDR in the snapshot mode?
If the answer to either of the above questions is no, then the decel stall condition maybe caused due to EMI induced on the crank sensor ckt .This EMI originates from the #4 cylinder firing event, through the spark plug wire into the ICM (from the #4 coil/ICM proximity), which is then transferred into the sensor ckt due to the proximity of the icm to the sensor ckt.
Verify spark plug and wire resistances are not excessive. S/P resistance should be 5000 ohms +/- 2500 ohms at approx 68 degrees F. S/P wires should not exceed 3000 ohms per foot.
Verify PCM grounds by using a voltmeter to check the voltage drop (should not exceed 40 MV ).
Verify fuel pressure during condition.
Check for possible carbon deposits formed on the IAC and EGR or in the throttle body passages.
Verify the ICM ground.
Verify all 4 ICM connectors are secure.
Verify crank A, B and cam sensor connector pins are not bent and that they are seated correctly circuit integrity.
Verify crank A, B and cam sensors are free of metal shavings. The metal shavings could distort the signal from the sensors to the ICM and cause misinterpretation of the data.
If the above checks are good and the condition can be easily duplicated, then swap #1 AND #4 spark plug wires at the coil and evaluate. if the condition is eliminated and spark plug and wire resistance checks are good, then install a revised crankshaft position a sensor(top sensor) . If condition remains, then swap #6 AND #7 spark plug wires. If this eliminates the condition, and spark plug and wire resistance checks are good, then install the revised crankshaft position sensor in position B (bottom sensor). Also, if the condition can be duplicated easily, the problem can be verified by using the Tech 2 manual snapshot feature to monitor engine RPM and 4X reference( engine 2 data). If engine RPM drops to approx. 400 RPM and 4X ref drops below 8 (usually 5 or 6) or above 8 (usually 10), this will most likely be seen in frame -1 just before stall in frame 0 of your manual snap shot.

[zengel442]

Have you resolved your issue? Was it the crank sensor ? and if so, which one?
I have about the same problem.. Put it in reverse and immediate stall. Plus the other idle speed fluctuations and stalling.
My car is a 95 Aurora with 110k - which one do you have?

[maxwedge]

Originally Posted by zengel442

Have you resolved your issue? Was it the crank sensor ? and if so, which one?
I have about the same problem.. Put it in reverse and immediate stall. Plus the other idle speed fluctuations and stalling.
My car is a 95 Aurora with 110k - which one do you have?

4 month old thread here, it looks like if you follow the lead in the last post you should pin down your problem.