92 F150 electrical issue

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Feb 9, 2022 | 12:37 PM

slysfarm

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Trailering

Joined: Nov 2020

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92 F150 electrical issue

Hello!! My 1992 F150, 5.0, 4 wheel drive is running like crap!. I changed the fuel filter a while back due to slight hesitation issues during accelerating. The truck ran beautifully for a couple of weeks then started having bizarre symptoms intermittently. The first symptom was losing power. I could floor the gas pedal and it would not pick up speed. I would have to pump pump pump for it to kick in. Sometimes this happened right away. other times it would happen after warming up. I don't drive the truck much and this didn't happen every time so I just lived with it. Gradually the problem worsened. It went from hesitating as if it was a fuel issue, to violently shaking during acceleration!! I noticed the rpm needle would jump around while this was happening so my mechanic changed out the ignition control module... needles jumping suggested this was an electrical issue. The first thing I noticed after starting the truck was the front gas tank gauge, which has not worked in over a year was now working. !! For 2 days the gauge worked then once again stopped. Now, let me back up a bit and explain. This weird vibrating, shaking, bogging during acceleration ended in such a violent shaking episode it felt like the truck was falling apart! then the truck died completely. Turns out I ran out of gas in that front tank. According to the odometer, I should have had at least 50 miles before empty. Obviously whatever was happening with the truck was now causing horrible gas mileage. . changing out the ignition control module appeared to help. problem solved right??NOT !! the truck ran great for a day or two then all symptoms are back. Next, I changed out the 02 sensor. No change. So this is what I am thinking.... I have noticed when shifting gears ( automatic) the gauge needles on the dash move. Every time I go from park to drive, drive to reverse, etc needles jump. I also noticed at night the headlights blip ( dim) ever so slightly. Obviously, I have a short somewhere. Being that the front gas tank mysteriously worked momentarily after changing the ICM,( coincidence ??) gauge needle movement, and headlights dimming while shifting, got me thinking the problem may be a loose wire or bad connection behind the dash????? Oh !! and one more thing.. The reason I decided to change out the 02 sensor was the discovery of a blown fuse under the hood. Why did this fuse blow?? I have a serious short issue. this truck is not drivable. Before I dive into taking apart the dash I wanted to put this out there to see if anyone else feels I may be on the right track???? The movement of shifting is the only time when needles jump and lights dim. Is it safe to assume the problem lies with wires closest to the steering wheel column???? A loose connection possibly at the gas gauge????? I have no idea what could be a coincidence? or connected. I am dead in the water and desperately need help. Paying a mechanic to figure out an intermittent short issue is not an option. Thank you for reading!!!

Feb 9, 2022 | 01:06 PM

slysfarm

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Trailering

Joined: Nov 2020

Posts: 15

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I also should mention that the truck starts right up every time. Its when you first turn the key all the gauge needles move. At idle you can hear a bit of a surge going up and down. when you give it gas and rev the engine, the rpm needle vibrates

Feb 10, 2022 | 12:25 AM

CathedralCub

FTE Community Team

Joined: Jan 2019

Posts: 10,781

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Maaaaybe the problem is the TPS . . . ?

I think swapping parts is not going to get you fixed. It's time for a real diagnosis, as in:

What is the fuel pressure when this is happening?

What is the voltage at the battery when this is happening?

Can you pull fuses one at a time to solve the issue at idle when this is happening?