Engine Bucks and Misfires When Cold - 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 11-26-2010
Member
Thread Starter
 
Join Date: Feb 2007
Location: Narragansett, RI
Posts: 21
Engine Bucks and Misfires When Cold

I have a 1997 Ranger 4x4 4.0L automatic. I have replaced the spark plugs and wires, fuel filter, and PCV valve all within the last 2 years. I also installed a Screaming Demon coil pack and gapped a new set of plugs to 0.063 two years ago. Twice within the last week or so when I started my truck in the morning it ran real rough, like it's misfiring or only running on 5 cylinders. It's misfiring so bad that it makes my truck shake and also bucks when I drive it. It does this when it's idling, accelerating, and cruising and in all gears, but seems to buck worse in 4th and 5th gear. What's weird is that it goes away shortly after my truck warms up and then my truck will run fine. It has done this to me once last week and did it again this morning. My truck has not thrown a check engine light unfortunately. I have read up on possible issues and I think that it might be a bad EGR valve, a fouled spark plug, or a bad fuel pressure regulator. It seems most likely to me to be a bad EGR valve, but I would assume that it would throw a check engine light. I'm just looking for other opinions before I spend the time and money on replacing parts while trying to chase down this issue.
Reply With Quote
  #2  
Old 11-26-2010
Member
 
Join Date: Mar 2007
Location: Upstate,NY
Posts: 2,598
Regap the plugs to .060 , check the insulators for cracks , and see if that helps.
Reply With Quote
  #3  
Old 12-30-2010
Member
 
Join Date: Mar 2010
Location: san jose
Posts: 6
mine dones this and i find that replacing spark plug #3 correct the issue. For some reason, this plug goes out every few months and when I replace it all is well.
Reply With Quote
  #4  
Old 01-13-2011
Member
 
Join Date: Dec 2008
Location: St. Louis, MO
Posts: 62
I have a 2000 4.0 and had this same problem. You may want to check your O2 sensor and intake manifold gasket. Those were the 2 things I had to replace and the truck runs great now.

I did have a CEL: Misfire on cylinder #3 that would come and go. When it first started acting up it would idle/run rough on a cold start then smooth out after a few minutes. After a while it got worse until it was rough all the time. Good luck.
Reply With Quote
  #5  
Old 01-28-2011
jtfoxman's Avatar
Member
 
Join Date: Jun 2005
Location: The Poconos
Posts: 891
Wirelessly posted

I'd check the O2 sensor. Recently same thing happened to me. No codes but I found that the last O2sensor was loose.
Reply With Quote
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
92 2.3 ranger misfires and bucks at high RPM 2.3limapower SOHC - 2.3L & 2.5L Lima Engines 2 12-02-2014 07:25 PM
P304 code. bucks/misfires at 4k rpm Lettuce_Boy 2.9L & 3.0L V6 Tech 6 04-10-2012 09:45 PM
3.0 misfires/bucks glindy 2.9L & 3.0L V6 Tech 1 04-04-2012 09:21 PM
Engine starts choking and misfires then starts to jerk violently 97ranger666 SOHC - 2.3L & 2.5L Lima Engines 3 10-09-2011 12:36 PM
Engine Occasionaly misfires Ray_Welder 4.0L OHV & SOHC V6 Tech 4 02-18-2008 10:53 AM


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 02:50 PM.


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.