Topic Sponsor
2004 - 2008 Ford F150 General discussion on the 2004 - 2008 Ford F150 truck.

Rough idle, need some help please

Thread Tools
 
Search this Thread
 
Old 04-25-2014, 07:45 PM
  #11  
Senior Member
 
primalurges's Avatar
 
Join Date: Mar 2009
Posts: 1,062
Received 49 Likes on 47 Posts

Default

Lean conditions are the result of insufficient exhaust has detection by o2 sensor. Yes, air leak after MAF can be the cause but it's usually the simple stuff that gets overlooked. Start with your spark plugs. When was the last time they were changed? If you don't know then they probably need changing especially with 320k on the clock. Coils may also be weak. Any idea what your fuel trim levels are at?
Old 04-25-2014, 08:04 PM
  #12  
Senior Member
 
primalurges's Avatar
 
Join Date: Mar 2009
Posts: 1,062
Received 49 Likes on 47 Posts

Default

Lean conditions are the result of insufficient exhaust has detection by o2 sensor. Yes, air leak after MAF can be the cause but it's usually the simple stuff that gets overlooked. Start with your spark plugs. When was the last time they were changed? If you don't know then they probably need changing especially with 320k on the clock. Coils may also be weak. Any idea what your fuel trim levels are at?
The following users liked this post:
roara (04-26-2014)
Old 04-26-2014, 05:58 AM
  #13  
Junior Member
 
Rezell04Lariat's Avatar
 
Join Date: Apr 2014
Posts: 4
Received 0 Likes on 0 Posts
Default

I am going to clean my TB next weekend. I am having the same rough idle issue on my 04 Lariat. I will update when I am done.
Old 04-26-2014, 12:13 PM
  #14  
Junior Member
Thread Starter
 
roara's Avatar
 
Join Date: Apr 2014
Location: Portland, Or
Posts: 7
Received 0 Likes on 0 Posts
Default

Thanks for the replies guys.
Old 04-26-2014, 12:18 PM
  #15  
Junior Member
Thread Starter
 
roara's Avatar
 
Join Date: Apr 2014
Location: Portland, Or
Posts: 7
Received 0 Likes on 0 Posts
Default

Originally Posted by MHOWELL34
Clean your throttle body guys! Go to Advanced get some MAF Cleaner and Deep Creep for that throttle body! Mine did the same and would even die if you played with the pedal at low rpm and rough idle. Had oil caked on the bottom of it and around the rim! Runs like a champ now!

Also try 5w30 thats what i'm running since im over 200k now. Does it have the Gott's mod? Could give that a whirl and see if itll make the MAF give you more gas to not be on lean side.
I did do a cursory cleaning of the TB without removing it. (it needs to be removed and done right) Seemed to change the symptoms a little bit. Now it idles a bit higher after cold start but settles down.
Old 04-26-2014, 12:24 PM
  #16  
Junior Member
Thread Starter
 
roara's Avatar
 
Join Date: Apr 2014
Location: Portland, Or
Posts: 7
Received 0 Likes on 0 Posts
Default

Originally Posted by uzikaduzi
I think cleaning the TB is just general good maintenance but if you're getting lean codes, you don't want to increase airflow... in fact lean conditions can be caused by increasing air flow with CAI's or even the Gott's mod... i would check the intake (starting at the filter) for leaks... if you don't get a seal on the air filter, it can suck too much air and throw lean codes
A proper functioning TB is ideal, it wouldn't be increasing air flow in a negative way tho. Intake leaks downstream of the MAF would be more of a concern than upstream, right?
Old 04-26-2014, 12:37 PM
  #17  
Junior Member
Thread Starter
 
roara's Avatar
 
Join Date: Apr 2014
Location: Portland, Or
Posts: 7
Received 0 Likes on 0 Posts
Default

Originally Posted by primalurges
Lean conditions are the result of insufficient exhaust has detection by o2 sensor. Yes, air leak after MAF can be the cause but it's usually the simple stuff that gets overlooked. Start with your spark plugs. When was the last time they were changed? If you don't know then they probably need changing especially with 320k on the clock. Coils may also be weak. Any idea what your fuel trim levels are at?
Good point. I have no idea when the last tune-up was but she's been running great for the past year I've been driving it.

This seemed to happen suddenly tho. I came across a thread on the FPDM, Fuel Pump Driver Module. There were many horror stories and pics of trashed modules. These are located on a frame rail above the spare tire. Great! Of course in my case the socket that goes on the end of the crank-stick is missing so I can't drop the spare! Les Schwab doesn't have a "key" or any of the other parts stores I checked. Dealer only I believe. I even checked with a few neighbors. One guy had an '02 and he had the crank-stick that fit right in to the pocket, no socket required.

Does this sound like FPR? Fuel Pressue Regulator? (if the FPDM is in good shape)
Old 04-26-2014, 01:22 PM
  #18  
Senior Member
iTrader: (1)
 
Especial86's Avatar
 
Join Date: Dec 2011
Posts: 5,741
Received 532 Likes on 438 Posts

Default

Originally Posted by roara
Good point. I have no idea when the last tune-up was but she's been running great for the past year I've been driving it. This seemed to happen suddenly tho. I came across a thread on the FPDM, Fuel Pump Driver Module. There were many horror stories and pics of trashed modules. These are located on a frame rail above the spare tire. Great! Of course in my case the socket that goes on the end of the crank-stick is missing so I can't drop the spare! Les Schwab doesn't have a "key" or any of the other parts stores I checked. Dealer only I believe. I even checked with a few neighbors. One guy had an '02 and he had the crank-stick that fit right in to the pocket, no socket required. Does this sound like FPR? Fuel Pressue Regulator? (if the FPDM is in good shape)
Also check for any exhaust leaks before the 02's, at the manifolds. I would put new front 02's in with over 300k miles.

With your milage I would absolutely do a full ignition system tuneup. You won't regret the peace of mind, and the elimination of countless variables with future and current trouble code diagnosis..

Go to the junkyard if you need to complete your OEM road hazard tool kit.
The following users liked this post:
roara (04-26-2014)
Old 04-26-2014, 01:33 PM
  #19  
Junior Member
Thread Starter
 
roara's Avatar
 
Join Date: Apr 2014
Location: Portland, Or
Posts: 7
Received 0 Likes on 0 Posts
Default

I'm headin for plugs right now. Technically the truck isn't mine yet but I'm ok with some basic tune-up stuff.
Old 07-22-2014, 10:14 AM
  #20  
Member
 
4.6LManual's Avatar
 
Join Date: Jun 2014
Location: Md
Posts: 59
Received 6 Likes on 6 Posts

Default

Originally Posted by uzikaduzi
I think cleaning the TB is just general good maintenance but if you're getting lean codes, you don't want to increase airflow... in fact lean conditions can be caused by increasing air flow with CAI's or even the Gott's mod... i would check the intake (starting at the filter) for leaks... if you don't get a seal on the air filter, it can suck too much air and throw lean codes
It's air sucking in AFTER the MAF- that's a lean code issue starter. FYI- oven cleaner is a great soot/gunk remover for any application.


Quick Reply: Rough idle, need some help please



All times are GMT -4. The time now is 12:45 AM.