Misfire issues - 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 07-27-2016
Member
Thread Starter
 
Join Date: Jul 2016
Location: Lexington
Posts: 2
Misfire issues

My 2000 Ford Ranger 4.0 OHV is having an issue, I know its not bad gas etc, it cranks a little rough at first but stops idling rough after a few seconds, then when I start down the road and it usually happens when I don't get on the throttle much, it'll start misfiring pretty bad but if I put the throttle to the floor it will stop, its not throwing any codes, I'm thinking its a vacuum leak somewhere but I have no clue, if someone can help thank you.
Reply With Quote
  #2  
Old 07-30-2016
cheese_man's Avatar
Member
iTrader: (1)
 
Join Date: Nov 2009
Location: arthur
Posts: 2,080
do you have cruise control
Reply With Quote
  #3  
Old 07-30-2016
RF Veteran
iTrader: (1)
 
Join Date: Jan 2014
Location: Vancouver, BC
Posts: 5,739
Welcome to the forum

Warm up engine
On the front, side, of upper intake is the IAC(idle air control) valve it has 2 wires plugged in to it.
While engine is idling(warm) unplug those wires, RPMs should drop to 500, or engine may even stall, either is GOOD, it means no vacuum leaks.
If idle is above 700 then there is a leak
Start unplugging vacuum hoses from intake and seal port with finger, when RPMs drop you found the hose with the leak.
If all hoses are OK then you will need to check intake gaskets.

Vacuum leak almost always causes a lean code
Reply With Quote
  #4  
Old 07-30-2016
cheese_man's Avatar
Member
iTrader: (1)
 
Join Date: Nov 2009
Location: arthur
Posts: 2,080
good advice from ron

several reports i read about almost always result from vacuum leaking from the cruise control vacuum bulb

mounted behind the front passenger side inner fender cover
Reply With Quote
  #5  
Old 08-10-2016
Member
Thread Starter
 
Join Date: Jul 2016
Location: Lexington
Posts: 2
Quote:
Originally Posted by RonD View Post
Welcome to the forum

Warm up engine
On the front, side, of upper intake is the IAC(idle air control) valve it has 2 wires plugged in to it.
While engine is idling(warm) unplug those wires, RPMs should drop to 500, or engine may even stall, either is GOOD, it means no vacuum leaks.
If idle is above 700 then there is a leak
Start unplugging vacuum hoses from intake and seal port with finger, when RPMs drop you found the hose with the leak.
If all hoses are OK then you will need to check intake gaskets.

Vacuum leak almost always causes a lean code
Thanks for the reply, I read a little more and browsed me and my dad checked for vacuum leaks and their fine, so I read more about my issue cause its not throwing any codes, I read that the closest thing to my issue is a cracked cylinder head.
Reply With Quote
  #6  
Old 08-10-2016
RF Veteran
iTrader: (1)
 
Join Date: Jan 2014
Location: Vancouver, BC
Posts: 5,739
4.0l OHV did have a weak spot between valve seats in the heads that could cause a crack if overheated.

But symptoms of that problem would also include a full overflow tank from too much pressure in cooling system and overheating if driven more than 15 minutes.

Misfire would be a secondary symptom
Reply With Quote
  #7  
Old 08-10-2016
cheese_man's Avatar
Member
iTrader: (1)
 
Join Date: Nov 2009
Location: arthur
Posts: 2,080
RON he has the SOHC 4.0L engine
Reply With Quote
  #8  
Old 08-10-2016
RF Veteran
iTrader: (1)
 
Join Date: Jan 2014
Location: Vancouver, BC
Posts: 5,739
2000 Ranger = 4.0l OHV, 4.0l SOHC started in 2001 model year

Explorers started getting 4.0l SOHC in 1997 as an option, but could still have the OHV until 2000 model year
Reply With Quote
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Gauge issues/heating issues/high oil pressure Fw87 General Ford Ranger Discussion 2 04-25-2015 11:08 PM
Junkyard Injector Swap - What fits what? Misfire issues. :( joecool1320 2.9L & 3.0L V6 Tech 5 08-21-2010 10:08 AM
Misfire 4,5,6 help. JDRead 2.9L & 3.0L V6 Tech 10 09-24-2008 01:10 AM
Engine misfire???? phatspeed7x 4.0L OHV & SOHC V6 Tech 4 07-02-2006 08:08 AM
Misfire TBarCYa 4.0L OHV & SOHC V6 Tech 5 02-23-2005 10:14 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 11:00 AM.