Idle problems
Member
Joined: Oct 2006
Posts: 18
Likes: 0
[QUOTE=kraemer94]
Just following up.....did cleaning the throttle body work out for you??
I've read up on how to do it by removing the entire throttle body from the engine block, and cleaning it using Gum Out Throttle Body cleaner and a baby bottle washing brush. One thing that I also heard as a resolution to this problem was cleaning the MAF AND the Idle Air Control (IAC) valve attached to the throttle body. I'm going to attempt to do all three this week. Any tips/suggestions on how to go about cleaning all 3 without causing further problems???
Thanks.
Originally Posted by JamesAtTECH
Kraemer94.....I'm having the EXACT same damn issue with my '98 F-150 V8 4.6L.
I will try cleaning the throttle body today. I really don't know what else to try. I will also try cleaning the MAF Sensor. It's hard to troubleshoot as it does not happen all the time. I could go two months with out it happening. It does have a ruff Idle when stoped at a light. I been searching on the internet and I see alot of people having a problem like this but no fix. My truck only has 75,000 miles on it.
I will try cleaning the throttle body today. I really don't know what else to try. I will also try cleaning the MAF Sensor. It's hard to troubleshoot as it does not happen all the time. I could go two months with out it happening. It does have a ruff Idle when stoped at a light. I been searching on the internet and I see alot of people having a problem like this but no fix. My truck only has 75,000 miles on it.
I've read up on how to do it by removing the entire throttle body from the engine block, and cleaning it using Gum Out Throttle Body cleaner and a baby bottle washing brush. One thing that I also heard as a resolution to this problem was cleaning the MAF AND the Idle Air Control (IAC) valve attached to the throttle body. I'm going to attempt to do all three this week. Any tips/suggestions on how to go about cleaning all 3 without causing further problems???
Thanks.
Technical Article Contributor
Joined: Oct 2005
Posts: 25,641
Likes: 19
From: MI
Baby bottle wash brush ? 
Hey whatever works right 
But Auto Zone or Murrays carry Automotive Pipecleaners that work much better and there cheap - come in different sizes and they last forever - I put them in a drill motor and go to town
Hey whatever works right But Auto Zone or Murrays carry Automotive Pipecleaners that work much better and there cheap - come in different sizes and they last forever - I put them in a drill motor and go to town
Member
Joined: Oct 2006
Posts: 18
Likes: 0
Originally Posted by jbrew
Baby bottle wash brush ? Hey whatever works right
But Auto Zone or Murrays carry Automotive Pipecleaners that work much better and there cheap - come in different sizes and they last forever - I put them in a drill motor and go to town
Hey whatever works right But Auto Zone or Murrays carry Automotive Pipecleaners that work much better and there cheap - come in different sizes and they last forever - I put them in a drill motor and go to town
More questions for those reading this thread:
FYI...the Mass Airflow Sensor (MAF), the throttle body, and the Idle Air Control (IAC) cannot be cleaned by myself. Damn...I'm that stupid about car engines.
Question....has anyone seen the disclaimer on the throttle body that states it should not be cleaned with throttle body cleaner because it has already has the "anti-gunk" stuff on it and cleaning it may remove it and cause further problems in the future?? I wiped my finger on the other side of the butterfly valve (side leading into the intake) on the throttle body, and it came up dirty and oily. Sure sign indicator that it has buildup and needs to be taken apart and cleaned?? Or..is this normal?
The MAF......what kind of Torx is used to take it off?? I bought a T-10, but I can't get a bite on the screw head. I guess it's idiot-proof if I can't unscrew it to clean it.
The IAC....if I take it off, do I have to replace a gasket/O-ring attached to the throttle body? What can I use to clean the IAF valve? WD-40? How difficult is it to take off??
Thanks.
Technical Article Contributor
Joined: Oct 2005
Posts: 25,641
Likes: 19
From: MI
I used vise grips myself - but there called safety torx , you can pic these up at a sears hardware or tools store. Some Auto suppliers carry them as well.
The IAC groumet is molded into the intake - so , no-worries there.
Anti - Sludge. Once you remove the TB - just use soap and water - it's easy to remove. Click on the link for some more info..
http://www.fordf150.net/howto/throttlebodyclean.php
The IAC groumet is molded into the intake - so , no-worries there.
Anti - Sludge. Once you remove the TB - just use soap and water - it's easy to remove. Click on the link for some more info..
http://www.fordf150.net/howto/throttlebodyclean.php
Last edited by jbrew; Jun 5, 2007 at 04:31 PM.
Junior Member
Joined: Jan 2009
Posts: 1
Likes: 0
************************************************** **********
For idle surge/hunting, the IAC is not being controlled by the PCM full time for whatever reason. Usually it's an IAC fault.
The IAC is "pulse" controlled against it's internal spring loaded dashpoted pintle so it results in a continiously smoothe control function since it is not a motor.
The throttle body is set to a small opening by a throttle stop and sets the min rpm the engine will idle at if the IAC fails. This setting also keep the throttle blade from sticking in it's bore when the engine cools. This is why this stop should never be adjusted unless someone has adjusted it out of spec.
The reason the idle hunts or surges is the idle speed is set in program. The crank pickup is the reference point the program uses to try to keep the idle within a tight rpm tolerence and tries to get the engine to match the program value within that tolerence. This is done by varying the IAC opening and the amount of air allowed to bypass the throttle plate.
Basicly a dealer tech should know that a hunting idle is the IAC action or a variable amount of unaccounted for air getting into the intake tract.
You must remember that the OX sensors also detect this and change fuel amount injected as another means of correcting the situation. This is a great part of the hunting that occurrs.
All areas have to be looked at or the problem never gets fixed.
Once again you are dealing with a full computer system and unless the operations are understood, the fixes can be a long time in coming except for some luck on well defined faults.
Good luck.
When the temperature is in the low 40s or less my engine won't idle very well at all. The RPM slowly drops with a very rough idle then surges back up on past 1000 RPMs. It's even died before. I have to keep the throttle opened up a bit to keep it running smooth. Runs fine though going down the road.
I've replaced the IAC with a brand knew one... twice. I just recently got an O2 sensor code but for the longest time I had no codes at all. I'm going to replace that soon. Any other ideas? It's only when cold, warm weather and it runs fine. No mechanics around here know what it is and I've talked to a lot of them.
I've quoted the above because I've replaced mine and was wondering if something else in the IAC system could cause it, like a wire or something? I've also been told it could be a bad computer.
Junior Member
Joined: Jan 2009
Posts: 11
Likes: 0
im new to the forum also but i am having the same problem. the codes at autozone indicates its a iac problem. either a bad connection or bad iac valve.the problem i have is i dony know where its at nor do the guys at autozone. i have a 2004 f150 with a 4.6l engine. its the new body style .if anyone could help it would be greatly appreciated. thanks
Technical Article Contributor
Joined: Oct 2005
Posts: 25,641
Likes: 19
From: MI
im new to the forum also but i am having the same problem. the codes at autozone indicates its a iac problem. either a bad connection or bad iac valve.the problem i have is i dony know where its at nor do the guys at autozone. i have a 2004 f150 with a 4.6l engine. its the new body style .if anyone could help it would be greatly appreciated. thanks
Cause you don't have one w/ETC sets.
Torque Based Electronic Throttle Control (ETC)
The ETC system basically replaces the standard cable operated accelerator pedal, idle air control (IAC) motor, 3-wire throttle position sensor (TPS) and mechanical throttle body.
could be the wires , body motor or PCM - You try cleaning the plate? You give no symtoms(or exact) and you haven't posted code - need the code so we know it was scanned correctly. Hard to help without info. The 04 is completly different. Try the search bar in engines and 04+ forums.
Good Luck
Junior Member
Joined: Jan 2009
Posts: 11
Likes: 0
Cause you don't have one w/ETC sets.
Torque Based Electronic Throttle Control (ETC)
The ETC system basically replaces the standard cable operated accelerator pedal, idle air control (IAC) motor, 3-wire throttle position sensor (TPS) and mechanical throttle body.
could be the wires , body motor or PCM - You try cleaning the plate? You give no symtoms(or exact) and you haven't posted code - need the code so we know it was scanned correctly. Hard to help without info. The 04 is completly different. Try the search bar in engines and 04+ forums.
Good Luck
Torque Based Electronic Throttle Control (ETC)
The ETC system basically replaces the standard cable operated accelerator pedal, idle air control (IAC) motor, 3-wire throttle position sensor (TPS) and mechanical throttle body.
could be the wires , body motor or PCM - You try cleaning the plate? You give no symtoms(or exact) and you haven't posted code - need the code so we know it was scanned correctly. Hard to help without info. The 04 is completly different. Try the search bar in engines and 04+ forums.
Good Luck
Junior Member
Joined: Jan 2009
Posts: 11
Likes: 0
the code is p0506
and states
iac circuit condition r idle speed higher/lower than expected. probable causes are:
1. vacuum leak on engine
2. dirty throttle body
3. iac motor defective
4. poor electrical connection to the iac valve
and states
iac circuit condition r idle speed higher/lower than expected. probable causes are:
1. vacuum leak on engine
2. dirty throttle body
3. iac motor defective
4. poor electrical connection to the iac valve