High idle and won't shift
Thread Starter
|
Freshman User
Joined: Feb 2007
Posts: 31
Likes: 0
High idle and won't shift
I have a 2002 Expedition with a 5.4L motor. When it gets really cold, like now, my idle goes way up into the 2k range and the trans doesn't shift up while driving. I can move the shifter from Drive to 2nd gear and get it to shift into second. However, it won't shift on it's own into any gear higher than first while in Drive. These two symptoms always happen together.
No check engine light or any other symptom of any kind.
Sometimes it will stop doing this but it is erratic. The problem doesn't change whether the engine is cold or hot. I just drove it home from work and it continued from start to finish with the problem.
It seems like an electrical issue since I can get the trans to shift into 2nd manually and because the high idle occurs too at the same time. I think I may be getting a bad signal from a sensor but can't tell which one.
I'm going out to check electrical plugs to see if any are loose or dirty.
Any help or suggestions appreciated.
Chris
No check engine light or any other symptom of any kind.
Sometimes it will stop doing this but it is erratic. The problem doesn't change whether the engine is cold or hot. I just drove it home from work and it continued from start to finish with the problem.
It seems like an electrical issue since I can get the trans to shift into 2nd manually and because the high idle occurs too at the same time. I think I may be getting a bad signal from a sensor but can't tell which one.
I'm going out to check electrical plugs to see if any are loose or dirty.
Any help or suggestions appreciated.
Chris
Freshman User
Joined: Dec 2004
Posts: 36
Likes: 0
Something very simular happened to my F150 the other day. The only difference is that mine was turining over 4500rpm's. It turned out to be a throttle position sensor.(TPS) It must have been sticking or somthing. It is on the driver side of the throttle body and has 3 wires going to it. It's only $29 at Auto Zone. Hope this helps.
Logistics Pro
Joined: Jan 2001
Posts: 3,740
Likes: 37
From: Central NYS
If I may ask, what was the clue that pointed you to the TPS?
Freshman User
Joined: Dec 2004
Posts: 36
Likes: 0
My Haynes manual suggestes checking the Idle Air Control (IAC) valve. It has 2 wires on it, I accidently unpluged the TPS which has 3 wires going to it. I couldn't find the IAC and I decided to start the engine again just to try it. It ran almost normal. I took it for a drive and the service engine light came on. When I read the code it indicated the TPS. If you have access to a code reader that reads pending codes have it read. There might be a code that hasen't triggered the light yet. Auto Zone will read it for free. Good Luck
Thread
Thread Starter
Forum
Replies
Last Post
Slash19
1999 - 2003 7.3L Power Stroke Diesel
11
May 11, 2024 09:06 PM
kendogg
Clutch, Transmission, Differential, Axle & Transfer Case
8
Nov 22, 2023 05:07 AM
Alsride
1999 - 2003 7.3L Power Stroke Diesel
29
Jul 25, 2016 09:27 PM
hillbilly469
1997 - 2003 F150
11
Dec 3, 2015 09:11 PM
mwistrom
Clutch, Transmission, Differential, Axle & Transfer Case
4
Aug 26, 2009 07:23 PM
