Rough Idle 2001 4.0 SOHC - Ranger-Forums - The Ultimate Ford Ranger Resource


4.0L OHV & SOHC V6 Tech General discussion of 4.0L OHV and SOHC V6 Ford Ranger engines.

Reply
 
LinkBack Thread Tools Search this Thread
  #1  
Old 04-22-2009
Member
Thread Starter
 
Join Date: Mar 2005
Location: Wichita, KS
Posts: 1,301
Rough Idle 2001 4.0 SOHC

For the past few months after the truck would heat up a little, the rpm's would drop to about 500 or 600 and idle rough. This happens while its in park and also while in gear. Occasionally it will die. I have 75,000 miles on it right now. I replaced the fuel filter back at 65,000 and just last night, I replaced all plugs and wires, thinking that this would fix the problem. Well that didn't fix it. I still have the rough idle at those low rpm's. I've been told to check the IAC but since I'm not getting a CEL light, it shouldn't be a sensor. Should I check this and how do I check the IAC? Is there something else I am missing? Should I check for a vacum leak around the intake manifold? Thanks for any help.
Reply With Quote
  #2  
Old 04-22-2009
Lazler's Avatar
Senior Member
iTrader: (18)
 
Join Date: Dec 2008
Location: Brantford, Ontario
Posts: 5,526
hope someone knows what's happening cause i have the same problem with the 4.0L in my explorer
Reply With Quote
  #3  
Old 04-22-2009
turbo's Avatar
Member
iTrader: (2)
 
Join Date: Aug 2007
Location: Tallahassee, FL
Posts: 565
Vacuum leak.

In my case, it was in the EGR line, right where it passes under the upper radiator hose. There's a little right-angle elbow there made out of reinforced rubber (that apparently tends to rot away after a while). Just pull the upper radiator hose out of the way and visually inspect it... on my truck, it was quite obvious. The part is not available at a standard auto parts store, but it's only around $30 from the dealer, and is the entire EGR assembly (not just that little rubber elbow). Takes all of 10 minutes to install.

My truck was performing exactly as you describe, above... and now it's running like a champ. Give it a check, and see if that's where your problem is...
Reply With Quote
  #4  
Old 04-22-2009
Member
Thread Starter
 
Join Date: Mar 2005
Location: Wichita, KS
Posts: 1,301
Quote:
Originally Posted by turbo View Post
Vacuum leak.

In my case, it was in the EGR line, right where it passes under the upper radiator hose. There's a little right-angle elbow there made out of reinforced rubber (that apparently tends to rot away after a while). Just pull the upper radiator hose out of the way and visually inspect it... on my truck, it was quite obvious. The part is not available at a standard auto parts store, but it's only around $30 from the dealer, and is the entire EGR assembly (not just that little rubber elbow). Takes all of 10 minutes to install.

My truck was performing exactly as you describe, above... and now it's running like a champ. Give it a check, and see if that's where your problem is...
Thanks, I'll check that out and see what it looks like.
Reply With Quote
  #5  
Old 04-22-2009
IN2 FX4's Avatar
Member
 
Join Date: Feb 2005
Location: Costa Mesa, CA
Posts: 855
That is not the EGR line, it is the PCV tube. Specifically it is the PCV elbow that disintegrates and causes the vacuum leak. I was able to find a silicone elbow that could be used instead of replacing the entire tube.
Reply With Quote
  #6  
Old 04-22-2009
turbo's Avatar
Member
iTrader: (2)
 
Join Date: Aug 2007
Location: Tallahassee, FL
Posts: 565
ah, okay.. thanks for the clarification. a car mechanic, I am not. ...but I can read a flowchart and follow directions. :D
Reply With Quote
  #7  
Old 04-22-2009
karrbass4life's Avatar
Member
 
Join Date: Nov 2004
Location: Cincinnati, Ohio
Posts: 3,072
Quote:
Originally Posted by turbo View Post
ah, okay.. thanks for the clarification. a car mechanic, I am not. ...but I can read a flowchart and follow directions. :D
If you can turn a wrench your halfway there.

It seems that PCV finds a way to wiggle out of the intake tube as well. I always check it in the summer since that seems to be the only time it happens.
Reply With Quote
  #8  
Old 04-22-2009
mcpink's Avatar
Member
iTrader: (1)
 
Join Date: Mar 2008
Location: Out There
Posts: 443
Had the same thing happen to mine. Quick, simple fix that doesn't cost a fortune.
Reply With Quote
  #9  
Old 04-22-2009
strakill's Avatar
Member
iTrader: (1)
 
Join Date: Jan 2009
Location: santa maria, Ca
Posts: 430
Had the same problem with the elbow breaking, paid the dealer 26 for both elbows and the 90* hose and fixed the problem
Reply With Quote
  #10  
Old 04-22-2009
David N's Avatar
Member
 
Join Date: Dec 2008
Location: Williamston, NC
Posts: 1,060
Cams, somebody must have swapped in some cams when you asleep one night! haha! J/M. Prolly a vaccum hose, had the same problem with my 302 in my other ranger. It was a vaccum line off on the MAP sensor.
Reply With Quote
  #11  
Old 04-24-2009
Member
Thread Starter
 
Join Date: Mar 2005
Location: Wichita, KS
Posts: 1,301
Quote:
Originally Posted by turbo View Post
Vacuum leak.

In my case, it was in the EGR line, right where it passes under the upper radiator hose. There's a little right-angle elbow there made out of reinforced rubber (that apparently tends to rot away after a while). Just pull the upper radiator hose out of the way and visually inspect it... on my truck, it was quite obvious. The part is not available at a standard auto parts store, but it's only around $30 from the dealer, and is the entire EGR assembly (not just that little rubber elbow). Takes all of 10 minutes to install.

My truck was performing exactly as you describe, above... and now it's running like a champ. Give it a check, and see if that's where your problem is...
Could you snap a quick photo when you get a chance, at the hose your talking about? I looked any my hoses look fine but with all the hoses and wires, I'm a little confused on the one your talking about.

Thanks.
Reply With Quote
  #12  
Old 04-26-2009
IN2 FX4's Avatar
Member
 
Join Date: Feb 2005
Location: Costa Mesa, CA
Posts: 855
If you do a search under "PVC elbow" you will find a thread I started. I posted pictures of that elbow.
Reply With Quote
  #13  
Old 04-26-2009
Member
Thread Starter
 
Join Date: Mar 2005
Location: Wichita, KS
Posts: 1,301
Thanks. Thats what I was looking for. Now to check that elbow and see if its causing the problem.
Reply With Quote
  #14  
Old 04-29-2009
Member
Thread Starter
 
Join Date: Mar 2005
Location: Wichita, KS
Posts: 1,301
Well I checked that hose and it seems fine. I didn't see anything wrong with it and there was no holes or cuts in it. Could it be a faulty IAC or MAF even though I'm not getting a CEL?
Reply With Quote
  #15  
Old 04-10-2011
Member
 
Join Date: Jun 2009
Location: campbell ca
Posts: 2
After reading this thread I went outside to my truck which had exactly this problem and my pcv elbow was shredded. I used rescue tape and tape the holes shut and my truck is running great! I also cleaned the MAF sensor and the throttle body plus put 3 zip ties on the throttle cable to get rid of the slack near the pedal and my truck is doing fantastic. Thank you guys for putting this up!
Reply With Quote
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
4.0 SOHC diagnosis? Rough idle/won't rev Sempertye 4.0L OHV & SOHC V6 Tech 20 11-03-2015 11:54 AM
2003 3.0 Ranger - rough low idle (400 rpm), bogs at 2500K, rough shift, NOW FINE ChargerOnDavins 2.9L & 3.0L V6 Tech 3 03-23-2015 04:25 PM
1995 rough idle/slow return to idle whiskeybreath SOHC - 2.3L & 2.5L Lima Engines 1 11-27-2014 05:06 PM
rough idle, 2003 4,0 sohc coleary15 4.0L OHV & SOHC V6 Tech 2 05-13-2011 09:27 AM
03 4.0 SOHC rough idle and DTC's Hanks Rangers 4.0L OHV & SOHC V6 Tech 12 08-07-2009 03:59 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -6. The time now is 02:28 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.