Idle Drop
Thread Starter
|
New User
Joined: Apr 2009
Posts: 9
Likes: 0
Idle Drop
On my 96 Limited with a 4L OHV, 141900 miles, once in awhile I'll be sitting at a stop light the engine will just idle rough and act like it wants to die. It doesn't, just acts like it. The trans in drive, foot on the brake, engine warm. Other than that, it runs great.
I get no codes.
Here's whats been done to it. At 139000 I changed plugs & wires, air filter, fuel filter and DPFE sensor.
I also get a strong smell of fuel sometimes, but not at the same time as when it starts to die.
I don't know if the two are related.
Anyone have an idea? or has it happened to them?
I'm at a loss, I can't duplicate the symptoms at home.
I get no codes.
Here's whats been done to it. At 139000 I changed plugs & wires, air filter, fuel filter and DPFE sensor.
I also get a strong smell of fuel sometimes, but not at the same time as when it starts to die.
I don't know if the two are related.
Anyone have an idea? or has it happened to them?
I'm at a loss, I can't duplicate the symptoms at home.
Senior User
Joined: Dec 2010
Posts: 253
Likes: 0
On my 96 Limited with a 4L OHV, 141900 miles, once in awhile I'll be sitting at a stop light the engine will just idle rough and act like it wants to die. It doesn't, just acts like it. The trans in drive, foot on the brake, engine warm. Other than that, it runs great.
I get no codes.
Here's whats been done to it. At 139000 I changed plugs & wires, air filter, fuel filter and DPFE sensor.
I also get a strong smell of fuel sometimes, but not at the same time as when it starts to die.
I don't know if the two are related.
Anyone have an idea? or has it happened to them?
I'm at a loss, I can't duplicate the symptoms at home.
I get no codes.
Here's whats been done to it. At 139000 I changed plugs & wires, air filter, fuel filter and DPFE sensor.
I also get a strong smell of fuel sometimes, but not at the same time as when it starts to die.
I don't know if the two are related.
Anyone have an idea? or has it happened to them?
I'm at a loss, I can't duplicate the symptoms at home.
Logistics Pro
Joined: Jun 2009
Posts: 4,808
Likes: 83
From: Cedar Rapids, IA
There are a lot of items that can cause the symptoms you describe. It's going to take some further troubleshooting to determine the likely cause, or you can shotgun a few parts. As mentioned above, it could be the Idle Air Control (IAC), but that would tend to cause more drastic issues when the engine is cold. It could be a vacuum line that is cracked and expands further when warm, causing a misfire condition. Knowing the Short Term Fuel Trim (STFT) and/or the O2 sensor voltages when the roughness occurs happens could help diagnose this. You might have a spark plug wire, spark plug, or fuel injector that is failing when hot as well. Again, knowing if the engine goes rich or lean when it starts to idle rough will help diagnose this.
A couple of common items that could cause rough idle and not necessarily trigger a diagnostic code would be a cracked PCV elbow (vacuum leak) or a leaking intake manifold gasket (vacuum leak).
-Rod
A couple of common items that could cause rough idle and not necessarily trigger a diagnostic code would be a cracked PCV elbow (vacuum leak) or a leaking intake manifold gasket (vacuum leak).
-Rod
Thread Starter
|
New User
Joined: Apr 2009
Posts: 9
Likes: 0
Ok I went out today and cleaned the IAC, drove for about 10 miles and it still does it. I have 18in of steady vacuum at idle. I checked the PCV elbow and its good.
The plugs and wires were replaced about 2000 miles ago. So now I'm leaning towards a bad injector. Unfortunately my scaner is a read-only type.
I did replace Bank1 Sensor O2 sensor when I did the tune-up.
Now could the fuel smell be related? It doesn't happen at the same time.
Thanks for the help
PJ
The plugs and wires were replaced about 2000 miles ago. So now I'm leaning towards a bad injector. Unfortunately my scaner is a read-only type.
I did replace Bank1 Sensor O2 sensor when I did the tune-up.
Now could the fuel smell be related? It doesn't happen at the same time.
Thanks for the help
PJ
Thread Starter
|
New User
Joined: Apr 2009
Posts: 9
Likes: 0
I smell it more when I'm sitting in the seat windows down and engine running. Either stopped or moving slow.
I stuggled with this because I wanted to make sure it wasn't anything else around me. It happens when the engine's warm. I smell it for a minute or so and then it disappears. the gas cap is good.
I'm just wondering if it could be an EVAP problem? It was a California truck.
PJ
I stuggled with this because I wanted to make sure it wasn't anything else around me. It happens when the engine's warm. I smell it for a minute or so and then it disappears. the gas cap is good.
I'm just wondering if it could be an EVAP problem? It was a California truck.
PJ
Thread
Thread Starter
Forum
Replies
Last Post
jdhudall
2009 - 2014 F150
5
Jan 11, 2017 11:28 PM
brokedownford
1987 - 1996 F150 & Larger F-Series Trucks
14
Oct 14, 2016 09:25 PM
RileyCarroll
1973 - 1979 F-100 & Larger F-Series Trucks
7
Aug 14, 2016 10:56 PM
cam4x4
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
32
Jul 31, 2011 08:56 PM
