Car stalling at idle

Tiny
GLENN GILBERT
  • MEMBER
  • 1997 DODGE AVENGER
  • 2.5L
  • V6
  • 2WD
  • AUTOMATIC
  • 153,000 MILES
Hello,

My car seems to be stalling and running rough when I am either at an idle or when I just start it and I am backing out of my driveway. My driveway is sloped and for some reason it tends to stall when I am on a slope. A friend of mine in Florida who owns an automotive repair shop seems to think it is the distributor. The car does start right back up when it does stall. I thought it might be the fuel pump but since it starts back up it may be the distributor. What do you think?
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Monday, February 11th, 2019 AT 3:24 AM

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Tiny
CARADIODOC
  • EXPERT
This is common if the battery was recently disconnected or run dead. The Engine Computer needs to see a specific set of conditions to relearn "minimum throttle". Until that takes place, you might have to hold the accelerator pedal down 1/4" for the engine to start and stay running, you won't get the nice idle flare-up to 1500 rpm at start-up, and it will tend to stall at stop signs.

To meet the conditions for the relearn to take place, drive at highway speed with the engine warmed up, then coast for at least seven seconds without touching the pedals.
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Monday, February 11th, 2019 AT 4:01 PM
Tiny
GLENN GILBERT
  • MEMBER
The battery was not recently disconnected. I have been having this problem for a while now. Like I said, I was told that the coil in the distributor was going bad or it could be the EGR valve. I am having no light come on in the dash but when I did it showed a couple of O2 sensors were bad, which I replaced. The one on bank 2, sensor 2 was covered with black carbon so I am thinking it might be the EGR valve but not sure. I did purchase an EGR valve but see that it is buried behind the intake manifold and I really am not comfortable about removing the intake unless there is a way to take the EGR off without removing the intake.
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Tuesday, February 12th, 2019 AT 3:42 AM
Tiny
CARADIODOC
  • EXPERT
If the EGR valve is not sealing properly, you will have rough idling too, but that won't cause it to idle too slowly. If you can loosen the mounting bolts, consider sliding in a thin piece of sheet metal shim to block the port temporarily. If the problem clears up, suspect that valve is blocked with a chip of carbon.

Don't worry about the pickup assembly in the distributor. Those are either good or bad, with no in-between, but they are very commonly intermittent, then work again once they cool down for an hour or so. If that assembly fails, the engine will not run at all.
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Tuesday, February 12th, 2019 AT 10:19 PM
Tiny
GLENN GILBERT
  • MEMBER
So what would be the cause of the car stalling especially on a slope? Could it possibly be the fuel pump or fuel filter? They both have been changed but not recently, around five years ago. If the EGR valve will not cause it to stall then I will not bother changing it, even though I purchased one but it is difficult to get to without pulling the intake which I really do not want to do.
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Wednesday, February 13th, 2019 AT 3:29 AM
Tiny
CARADIODOC
  • EXPERT
If the EGR valve is not sealing properly, the exhaust gas will dilute the incoming air which will make the engine idle too slowly and rough, however, the Engine Computer will raise idle speed back to specs. The way to see if that is taking place is to use a scanner to view the "idle steps". The computer places the automatic idle speed motor to one of 256 positions, or "steps". As the motor's shaft slowly rotates, it turns a threaded shaft that retracts or extends a pintle valve. That valve opens an air passage around the throttle blade. At the same time, it increases the amount of time it pulses the injectors open to provide more fuel to go with that extra air.

If you find the AIS step is "0", minimum throttle needs to be relearned. Under normal conditions you'll find it to be around step 32. With a single-cylinder misfire on a V-6 or V-8 engine, it will be somewhere around step 50. If you find the step number is quite high but idle speed is too low, either the AIS motor is stuck or the air passage is blocked with carbon. That carbon used to be a common cause of low idle speed in the late '80s and early '90s on some engines, but with the better fuel additives we have today, that problem is rarely seen now.

You can also use the scanner to raise idle speed to 2000 rpm in 200 rpm increments. That tests the AIS motor and wiring, and proves the computer has control of it. On some models, this test will not respond if minimum throttle hasn't been learned yet. Also, this test doesn't change idle speed that is programmed into the computer. Once the test is stopped, idle speed goes back to specs.

The fuel pump should not be related to this problem. The pickup sock sits in a small bowl in the middle of the tank. That prevents gas from running away from the pickup when you go around corners. The bowl is kept full by the very high volume of gas that gets pumped to the engine, then returns through the pressure regulator and the fuel return hose. If there is something wrong inside the tank, you will observe different symptoms depending on how much gas is in the tank.

You might consider checking the fuel pressure, but it has to be pretty low to cause running problems. Specs for your engine is 47 - 50 psi.
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Wednesday, February 13th, 2019 AT 3:34 PM

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