Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Nissan Quest 2007 revs up slightly when brake is applied

Recently, couple of maintenance were done. 3 sensors ( Camsoft/cranksoft) sensors were replaced and also Throttle Body was replaced. We have also done many times Throttle Body relearn process.
Our Idle is about 750 to 800 range. I have noticed when I am driving and when I first press brake padel then I see speed/rpm’s goes up slightly which is kind of weird but no problem in stopping it.
Other issue is when I let go gas pedal on lower speed e.g. 30mph, it looks like it takes slightly longer time ( more than 5 seconds) to slow down speed , it feels like it is going on for same speed for couple seconds even though I let go gas pedal. There is no code in scanner.
What needs to be checked ?

Vacuum hoses my wag.

I would add to barkydog’s post below by saying after checking the hoses, check the brake booster.

1 Like

That was my first thought as well.

1 Like

Hi Guys,
Is there any simple DIY method you guys can recommend to test out ?

The first thing to do is a visual inspection of the vacuum lines and fittings. Then:

  1. Verify that the symptom occurs with the engine running but the van in Park.
  2. Disconnect the vacuum line to the booster and plug the line going to the engine. Does the revving occur when you step on the brake?
  3. Connect a vacuum pump to the booster, and pump to around 15-20 PSI. Does the booster hold vacuum?
1 Like
  1. Verify that the symptom occurs with the engine running but the van in Park.
    When in park and engine running, pressing brake does not revs up RPM.
    I have also tried let engine run for few mins while in park and press brake pedal and turn off engine while looking whether I see any upward pressure on my leg for next 30 seconds but I did not see any issues holding up brake pedal for 30 seconds or longer.

Does it rule out issue with Brake Booster ?

Do Brake Booster Valve needs be checked further or above check rules out Brake Booster and Booster Valve issue ?
Will check No 2 and 3 soon too