Help with idle issues...please (confirm) - 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.

LinkBack Thread Tools Search this Thread
Old 06-10-2009
Thread Starter
Join Date: Mar 2006
Location: Loudon, NH
Posts: 77
Help with idle issues...please (confirm)

I have a 99 4.0 4x4 with ac. All stock (motor wise). Truck has some idle issues. It basically surges up and down from stall to 1k rpms. Trick is its not very consistant. Seems to do it when truck is hot, but not every time. It will work fine on my way to work in the morning, unless I shut it off (at store) then it surges and sometime stalls. After I run it for the rest of the trip to work it will be idling fine when I get there. Thought it was the IAC but wouldnt that be consistant? Cleaned maf and iac with no luck. No obvious leaks in vacuum (tested with carb cleaner). Last year I replaced the front hubs with AVM's and never capped the vacuum lines, but doesnt appear to be the issue. Only at idle or coming down from higher rpm. Occasionally can correct it by reving it up. Unplugging maf stalls the truck almost instantly. Just dont want to throw down the $70 on an IAC unless it sounds reasonable that it could be it (even being intermitent). TPS? doesnt seem likely correct? The rest of the ride is fine. Seems like a needle valve sticking in a carbed truck.
Reply With Quote
Old 06-10-2009
rolsmojave3's Avatar
Level III Supporter
Join Date: Jun 2006
Location: Wisconsin
Posts: 2,852
4.0 OHV engines are known for vacuum leaks at the intake manifold gaskets. Even if you did try it with some carb cleaner or whatever you might not catch it. I know I never caught mine with any kind of spray I just ended up replacing them because I was tired of it, and they were torn.
Reply With Quote
Old 06-10-2009
FullThrottle02's Avatar
iTrader: (3)
Join Date: Apr 2008
Location: McHenry,IL
Posts: 586
If you didn't plug the hub vac. lines I would start there. Then look for other vacuum leaks. It does sound like a IAC problem though.
Reply With Quote

Related Topics
Thread Thread Starter Forum Replies Last Post
Confirm my diagnosis of bad front hub bearing? Dalmatian90 Drivetrain Tech 4 11-29-2008 01:37 PM
98-03 and 04-0? Upper Balljoints? confirm Redneckstone Suspension Tech 4 02-04-2008 05:20 AM
Can someone confirm these stock exhaust size measurements? 05RangerXLT General Ford Ranger Discussion 4 11-25-2007 08:21 PM
Confirm my gauge cluster swap idea Needforspeed3685 General Technical & Electrical 5 08-11-2007 11:25 AM
Confirm my tranny fears... b3kbruiser General Technical & Electrical 15 11-30-2006 09:51 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 12:05 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 and affiliated sites.