low idle rpm?

[xz96]

When I put it in Park or Neutral, the idle rpm is a little bit less than 1000
When I put it in D or R and holding brake pedal, the idle rpm sometimes is a little bit less than 500, sometimes it's only about 200, sometimes it's 700-800

is it normal? is it too low?
truck runs fine and starts fine
i have a 99 explorer 2dr 2wd 4.0 sohc

my truck break down in a road trip, so I'm trying to fix any potential problem that might cause bigger problem in the future..

 

[2000StreetRod]

Idle speeds

The stock idle speeds commanded by the PCM for my strategy (CDE4) are 624 rpm for drive and 656 for drive with no adder for the A/C being on. You might try cleaning the IAC valve if yours is low.

 

[gmanpaint]

Sounds like a torque converter issue.

 

[2000StreetRod]

brake pedal position switch?

Good point gmanpaint! If the brake pedal position (BPP) switch is faulty the torque converter may stay locked at idle and the engine often will stall. An easy way to test the BPP switch is to engage cruise control and then tap the brake pedal. If cruise control stays engaged the BPP switch either needs adjustment or is defective.

 

[xz96]

Good point gmanpaint! If the brake pedal position (BPP) switch is faulty the torque converter may stay locked at idle and the engine often will stall. An easy way to test the BPP switch is to engage cruise control and then tap the brake pedal. If cruise control stays engaged the BPP switch either needs adjustment or is defective.

my brake pedal will turn off cruise control as soon as i tap it