Check Engine Light coming on intermittently
Thread Starter
Junior Member
Joined: Mar 2011
Posts: 16
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From: Minneapolis
Check Engine Light coming on intermittently
Hey,
I have this brand new 1994 F150 4.9L 6Cyl Long Box with about 144K miles on it.
Last week I took it from Minneapolis to Chicago for the weekend - about 420 miles one way.
The truck held up just fine for the whole 900 mile trip but I had this odd happening.
Whenever I am cruising at about 75 mph and have to ease off the gas for whatever reason, (someone cutting in front of you or adjusting speed for merging vehicles) the Check Engine Light will come ON.
It stays ON for about 20 seconds until I accelerate again and it will go away.
Decelerating - Comes ON
Accelerating - Turns OFF
Other probably relevant information:
-----------------------------------
At least one of the gas tanks were full.
I have this brand new 1994 F150 4.9L 6Cyl Long Box with about 144K miles on it.
Last week I took it from Minneapolis to Chicago for the weekend - about 420 miles one way.
The truck held up just fine for the whole 900 mile trip but I had this odd happening.
Whenever I am cruising at about 75 mph and have to ease off the gas for whatever reason, (someone cutting in front of you or adjusting speed for merging vehicles) the Check Engine Light will come ON.
It stays ON for about 20 seconds until I accelerate again and it will go away.
Decelerating - Comes ON
Accelerating - Turns OFF
Other probably relevant information:
-----------------------------------
At least one of the gas tanks were full.
Thread Starter
Junior Member
Joined: Mar 2011
Posts: 16
Likes: 0
From: Minneapolis
Thanks, I will find a way to get the codes.
No, there was no issues, it runs as smooth as ever, with no hiccups. That, and the fact that I was in rural Wisconsin at close to midnight with no hope of finding a mechanic led me to ignore the Check Engine Light (with no consequences, as it turned out).
No, there was no issues, it runs as smooth as ever, with no hiccups. That, and the fact that I was in rural Wisconsin at close to midnight with no hope of finding a mechanic led me to ignore the Check Engine Light (with no consequences, as it turned out).
Thread Starter
Junior Member
Joined: Mar 2011
Posts: 16
Likes: 0
From: Minneapolis
Umm... I figured out the engine light problem. It happens only when one or both tanks are full and it has to do with fuel sensors acting up.
It is actually mentioned in the owner's manual.
It is actually mentioned in the owner's manual.
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From: Long Beach Calimexifornia
Check the gas caps. Are they the correct type & are they sealing (check seal for cracks)? Old style key locking can do this too.
Thread Starter
Junior Member
Joined: Mar 2011
Posts: 16
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From: Minneapolis
I will look up the exact page numbers.
From what I remember, it is mentioned right where it talks about Check Engine Light. It says to ignore the CEL if it goes away after being turned on briefly.
From what I remember, it is mentioned right where it talks about Check Engine Light. It says to ignore the CEL if it goes away after being turned on briefly.
Thread Starter
Junior Member
Joined: Mar 2011
Posts: 16
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From: Minneapolis
@Ymeski56
You could be right. It has something to do with the caps not providing air flow to keep the pressure inside the fuel tank normal. (Or something like that)
If I stop the truck and inspect, I see that the rear tank has too high air pressure in there, which gets a relief if I remove the cap.
I will probably replace the cap and see if that is the source of this imbalance.
You could be right. It has something to do with the caps not providing air flow to keep the pressure inside the fuel tank normal. (Or something like that)
If I stop the truck and inspect, I see that the rear tank has too high air pressure in there, which gets a relief if I remove the cap.
I will probably replace the cap and see if that is the source of this imbalance.