1994 5.0 bogging under load, up and down idle
04-18-2018, 10:21 AM
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1994 5.0 bogging under load, up and down idle
1994 with 5.0. Runs great until it reaches operating temp. Then it starts losing all power. Bogs down. After you keep the throttle down for a minute or floor it it’ll pick right back up and run fine for about 30 seconds. And do it again. Will not do it if you keep it around 80-90 mph. Does it the worst between 45-60. So it seems it is the worst with steady pressure on the throttle. Or trying to slowly accelerate in that speed range. When it initially picks back up sometimes you can hear a loud knock from the lower driver side engine area.
Cold idle is great. But once again when it reaches operating temp it idles pretty rough and revs up and down.
I have replaced
plugs, wires, cap, button, coil, ICM, TPS, MAF ,IAC, fuel filter , I see this problem a lot on forums with no clear cut answer. Any help would be greatly appreciated.
Cold idle is great. But once again when it reaches operating temp it idles pretty rough and revs up and down.
I have replaced
plugs, wires, cap, button, coil, ICM, TPS, MAF ,IAC, fuel filter , I see this problem a lot on forums with no clear cut answer. Any help would be greatly appreciated.
04-18-2018, 11:02 AM
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You (and probably most others you've read) haven't told us enough of the truck's history or details for us to know how the truck is built, how it has been maintained, how much abuse/neglect it has suffered, how many miles it has done.... If we don't have a clear understanding of the truck's condition, we can't begin to guess at why it might exhibit any particular symptom. We also need to know when (time/miles) the symptom appeared, and how it progressed (sudden or gradual). Click this & read the caption:
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DON'T POST that info - put it in your signature so we can see it below each of your posts.
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For EACH part you've replaced, we need to know: when, why (maintenance or some symptom; what test did the original fail), with what (brand, PN, source), and did the replacement pass the same test the original failed? If any were replaced for THIS symptom, you should put the originals back on since you know they weren't the cause, and they're probably better than the new parts. What is the fuel pressure? Has a compression test been done on the engine recently? Do you have & know how to use a digital multimeter (DMM) to test the sensors & actuators? Do you have a Haynes manual, and have you read it?
(phone app link)
DON'T POST that info - put it in your signature so we can see it below each of your posts.
https://www.f150forum.com/profile.php?do=editsignature
For EACH part you've replaced, we need to know: when, why (maintenance or some symptom; what test did the original fail), with what (brand, PN, source), and did the replacement pass the same test the original failed? If any were replaced for THIS symptom, you should put the originals back on since you know they weren't the cause, and they're probably better than the new parts. What is the fuel pressure? Has a compression test been done on the engine recently? Do you have & know how to use a digital multimeter (DMM) to test the sensors & actuators? Do you have a Haynes manual, and have you read it?
03-27-2024, 06:12 PM
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1994 with 5.0. Runs great until it reaches operating temp. Then it starts losing all power. Bogs down. After you keep the throttle down for a minute or floor it it’ll pick right back up and run fine for about 30 seconds. And do it again. Will not do it if you keep it around 80-90 mph. Does it the worst between 45-60. So it seems it is the worst with steady pressure on the throttle. Or trying to slowly accelerate in that speed range. When it initially picks back up sometimes you can hear a loud knock from the lower driver side engine area.
Cold idle is great. But once again when it reaches operating temp it idles pretty rough and revs up and down.
I have replaced
plugs, wires, cap, button, coil, ICM, TPS, MAF ,IAC, fuel filter , I see this problem a lot on forums with no clear cut answer. Any help would be greatly appreciated.
Cold idle is great. But once again when it reaches operating temp it idles pretty rough and revs up and down.
I have replaced
plugs, wires, cap, button, coil, ICM, TPS, MAF ,IAC, fuel filter , I see this problem a lot on forums with no clear cut answer. Any help would be greatly appreciated.