high idle speed
03-15-2011, 10:13 PM
#1
Junior Member
Thread Starter
Join Date: Nov 2009
Posts: 8
Likes: 0
Received 0 Likes
on
0 Posts
high idle speed
2011 Scab 5.0L
When I put the truck in drive and press on the accelarator the engine acts as though it has a choke and will not idle back down it will just stay at what ever rpm I ran the engine up to. This does not happen when it is in reverse or park, just drive and it happens everytime I press lightly on the accelarator. I took it back to the dealer and on their first attempt they didn't fix it their second attempt will be Wednesday, but in the mean time does anybody know what may cause this?
I moved this tread here after posting it in the general section.
When I put the truck in drive and press on the accelarator the engine acts as though it has a choke and will not idle back down it will just stay at what ever rpm I ran the engine up to. This does not happen when it is in reverse or park, just drive and it happens everytime I press lightly on the accelarator. I took it back to the dealer and on their first attempt they didn't fix it their second attempt will be Wednesday, but in the mean time does anybody know what may cause this?
I moved this tread here after posting it in the general section.
03-15-2011, 10:36 PM
#2
Junior Member
Join Date: Mar 2011
Posts: 8
Likes: 0
Received 0 Likes
on
0 Posts
Hey,
I work at Advance Auto Parts and I see this problem frequently. 9 out of 10 times it ends up being either the TPS or the IAT, Throttle positioning sensor or Intake air temperature. The TPS lets the ecu know what position your throttle blade is that so it knows if you are trying to accelerate, coast or deccelerate. Accordingly it then calculates the amount of fuel needed in the cylinders based on your IAT which measures the temp on the intake charge and corresponds to a certain air density value allowing the ecu to know the amount of oxygen in the air that your truck is breathing. If either of them malfunctions then the ecu doesn't know what you're trying to do with the car as far as speed going so you do not get the proper amount of fuel and your car is in a "limp mode" or a fail safe mode so that you don't lean out and cause damage (too much air, not enough fuel). Similarly if the IAT is bad then the ecu doesn't know the density of the air and cannot properly calculate the amount of fuel needed to supply proper power so you will feel a similar power loss in the "limp mode".
Hope that helps a bit, the tech's at the dealer likely tried those first.
I work at Advance Auto Parts and I see this problem frequently. 9 out of 10 times it ends up being either the TPS or the IAT, Throttle positioning sensor or Intake air temperature. The TPS lets the ecu know what position your throttle blade is that so it knows if you are trying to accelerate, coast or deccelerate. Accordingly it then calculates the amount of fuel needed in the cylinders based on your IAT which measures the temp on the intake charge and corresponds to a certain air density value allowing the ecu to know the amount of oxygen in the air that your truck is breathing. If either of them malfunctions then the ecu doesn't know what you're trying to do with the car as far as speed going so you do not get the proper amount of fuel and your car is in a "limp mode" or a fail safe mode so that you don't lean out and cause damage (too much air, not enough fuel). Similarly if the IAT is bad then the ecu doesn't know the density of the air and cannot properly calculate the amount of fuel needed to supply proper power so you will feel a similar power loss in the "limp mode".
Hope that helps a bit, the tech's at the dealer likely tried those first.