Lean reading at idle
Thread Starter
|
New User
Joined: Apr 2003
Posts: 8
Likes: 0
Lean reading at idle
Hi everybody. I have a 1997 Club wagon with the 5.4L engine. When I start it in the morning (40 F Degrees) the RPMs drop and it just about stalls (real rough). When it warms up, it runs fine. I took it to the mechanic and the analyser said that it is running lean at idle (both O2 sensors). The computer is making it as lean as it can. Is there a common problem with this year and engine. Thanks, Bill
Hotshot
Joined: Aug 2002
Posts: 12,679
Likes: 15
From: BC, Canada
Lean reading at idle
Hi bill5.4l and welcome to FTE 
A couple things come to mind here. The rpm drop could be caused by a faulty IAC. It is quite common.
The lean code for both banks could be due to a dirty MAF sensor, or possibly a vacuum leak.
If you hit the search button near the top of the page and search for those things you'll find some info on them.
Let us know how it goes.
A couple things come to mind here. The rpm drop could be caused by a faulty IAC. It is quite common.
The lean code for both banks could be due to a dirty MAF sensor, or possibly a vacuum leak.
If you hit the search button near the top of the page and search for those things you'll find some info on them.
Let us know how it goes.
Thread Starter
|
New User
Joined: Apr 2003
Posts: 8
Likes: 0
Lean reading at idle
Hi Racerguy,
I cleaned the MAF sensor, injectors, changed the fuel filter, but cannot find a vacuum leak. The long term fuel trim is still showing +25% at idle after resetting the ECU. I still need to clean the IAC for the idle problem. Can this make the long term fuel trim read a high percentage?
Thanks,
Bill5.4l
I cleaned the MAF sensor, injectors, changed the fuel filter, but cannot find a vacuum leak. The long term fuel trim is still showing +25% at idle after resetting the ECU. I still need to clean the IAC for the idle problem. Can this make the long term fuel trim read a high percentage?
Thanks,
Bill5.4l
Hotshot
Joined: Aug 2002
Posts: 12,679
Likes: 15
From: BC, Canada
Lean reading at idle
No the IAC shouldn't affect your LFC.
Did he look at the MAF voltage when he checked things?
Did you check your fuel pressure? It can really mess things up if it isnt where it should be.
Any trouble codes?
If it looks ok and you cant find a vacuum leak I'd be inclined to suspect the O2s.
Did he look at the MAF voltage when he checked things?
Did you check your fuel pressure? It can really mess things up if it isnt where it should be.
Any trouble codes?
If it looks ok and you cant find a vacuum leak I'd be inclined to suspect the O2s.
Lean reading at idle
Thread
Thread Starter
Forum
Replies
Last Post
cscott952
1987 - 1996 F150 & Larger F-Series Trucks
10
Sep 10, 2016 06:34 AM
