All Big Six Losing all power randomly for a brief second

Relates to all big sixes

Will nicholson

New member
So ive got a 1996 f-150 4.9 with the 5 speed with no engine codes being thrown, my problem is that in the past few days my truck has randomly started losing all power while driving for a brief second and then its back and then it will do it again a few miles down the road any ideas what it could be?
 

jason832

Well-known member
If you provide more info about the truck itself and exactly how it's behaving the guys will be able to help you a bit better. Without more info it's a shot in the dark.
 

bubba22349

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Since its an intermittent problem I would look at all the electrical conections cleaning them up good and also all the grounds first. Just a little bit of time to do the job and very little cost involved, then see if it's there. Best of luck
 

Will nicholson

New member
So ive got a 1996 f-150 4.9 with the 5 speed with no engine codes being thrown, my problem is that in the past few days my truck has randomly started losing all power while driving for a brief second and then its back and then it will do it again a few miles down the road any ideas what it could be?
My gas mileage also went down, but i put a fuel pump in it not even 3 weeks ago
 

Will nicholson

New member
If you provide more info about the truck itself and exactly how it's behaving the guys will be able to help you a bit better. Without more info it's a shot in the dark.
I had my fuel pump replaced like 2 weeks ago and it has ran fine since then, no chrck engine lights and has sounded great, but lately after it warms up and im driving, the rpm plummets, not so much where it shuts off but i loose all power. I also just replaced my alternator the day before the fuel pump, my mpg is usually around 16 but its now at like 14 and thats doingn my best to barely use the throttle
 

sdiesel

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go directly to your pump and check your grounds , do not pass go do not collect.... you get the idea. you have,as mentioned, connectivity problems. follow up by a fuel pressure reading with a good gauge.
i thin the 6 is about 60 pounds but yor book will tell you
 

Econoline

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Check the grounds near the battery that are connected to the fender. I had this happen several years ago randomly on my 93 and that was the problem. There was one ground that would kill the entire truck when loose.
 

bubba22349

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Where the alternator and fuel pump actually bad or was this done because of the same intermittent power loss.
 

sixtseventwo4d

Well-known member
Assuming you put a fuel filter also......
Even a new fuel pump can act erratic, like sdiesel said, do a fuel pressure test, while driving. Check the ignition system thoroughly. Cap and rotor are easy enough to inspect physically, if you have any doubts about the wires; just replace them.
Do you have a scan tool? one that allows you to read the data stream?
 

MechRick

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If the intermittent power loss wasn't there before the alternator and fuel pump were replaced, I would start there. Go over your work, make sure your connections are good...
 

sdiesel

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bucking...is spark cut-out. this im also experiencing. i just restart and keep going. its a fantastic amount of work to keep these efi systems healthy at this age. (both myself and the truck). you may find bad connections (probable) grounds, or spark plug wires. its very time consuming to go through these systems looking for weak voltage signal and often its unproductive. eventually you will find the problem and it will be very simple, the search is fairly complex and requires patience, and a real desire to understand these systems, which are magnificent in design, but like an aging beauty you can only imagine what once was. its faair to say the wiring is likely your source of trouble.
 

arse_sidewards

Famous Member
Another vote for something on the high voltage side of the ignition. My Ranger and Aerostar (same exact EFI and ignition system as a 300) both did this. Cap, rotor and plug wires fixed it both times. The cap and rotor on the Ranger were so bad I'm impressed it even ran at all.
 

Will nicholson

New member
Another vote for something on the high voltage side of the ignition. My Ranger and Aerostar (same exact EFI and ignition system as a 300) both did this. Cap, rotor and plug wires fixed it both times. The cap and rotor on the Ranger were so bad I'm impressed it even ran at all.
See i thought that but im only 17000 miles on the plugs wires and cap on this truck that the previous owner had replaced with receipts to prove
 

Will nicholson

New member
Another vote for something on the high voltage side of the ignition. My Ranger and Aerostar (same exact EFI and ignition system as a 300) both did this. Cap, rotor and plug wires fixed it both times. The cap and rotor on the Ranger were so bad I'm impressed it even ran at all.
Do you think it could still be worth it to just switch them out
 

InlineDave87

Well-known member
Watching to see the results... i see you have a 96, i live in south texas and have a really good code reader that we could have done a lot of troubleshooting before opening it up since it should be an obd2 truck... im thinking of swapping my truck to obd2 for this very reason
 

Will nicholson

New member
Watching to see the results... i see you have a 96, i live in south texas and have a really good code reader that we could have done a lot of troubleshooting before opening it up since it should be an obd2 truck... im thinking of swapping my truck to obd2 for this very reason
I am also in south texas aswell, san antonio area?
 
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