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98 silverado random shut off.

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Old Nov 26, 2025 | 4:19 PM
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Default 98 silverado random shut off.

my grandson has a 98 1500 4wd that we recently purchased from an estate sale. it only has 154k on it and it is really good shape, i drove it home from the purchase place and it was a two hour drive in the dark, i had no issues. now my grandson has started driving it and it has a random shutdown. the engine just shuts off while driving and wont restart for about 30 seconds. sometimes longer. i took the truck and tried to get it to do it, but it didnt have any issues, he came and picked it up and went ten miles and it shut off. then it restarted no problem. nut it kept shutting off, sitting in his driveway running we tried everything i could think of. turned the wheels, turn signals, brakes, shook all wires, tapped on maf. nothing. but it will just die. but i cant make it do it. will not having a thermostat installed cause anything like that? i know it doesnt have one because it doesnt get warmed up above 160 or so, any ideas???
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Old Nov 27, 2025 | 4:38 PM
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also, i forgot to mention, when it shuts down, it looses power to everything and it takes usually about 30 seconds before everything will power back up and it will restart, it just turns off and you have to wait until the dashlights back up before it will start again, it doesnt matter if you turn the key off or take it out, you can try to start it but nothing until the dash lights come back on.
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Old Nov 29, 2025 | 10:18 PM
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The random shutoff is a classic sign of a failing Ignition Control Module. It's under the distributor cap. When it gets hot, it fails and the engine dies. It works again after it cools down for a minute.
The Crankshaft Position Sensor is another very common cause for this. It's a good idea to replace both.
You must install a thermostat. The engine computer needs the engine to get to normal temperature to run properly. The missing thermostat is very likely contributing to the problem.
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Old Dec 1, 2025 | 3:22 PM
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wil that cause a lose of power to everything? this has no power from the under hood fuseblock. battery still shows 13 volts. nothing works, no crank, no horn, no headlights, nothing. then after a minute or so, everything comes back on. and then it will star back up.
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Old Dec 1, 2025 | 4:08 PM
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I would have said the ICM, but that would not kill power to everything - you would just get a crank and no start. Unhook & clean your battery cables, even if they look ok. Any idea how long it sat before you bought it??
Regarding temp - you could have a thermostat present and working fine, but maybe the gauge or sender is faulty.

Last edited by Rednucleus; Dec 1, 2025 at 4:10 PM.
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Old Dec 1, 2025 | 7:23 PM
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already did the bat cables. trying to trace power to the main fuse box under the hood from battery. didnt set too long. drove it three hours straight when we got it. then drove it short distances. then it started this up about a month after that. it even does it when not driving, just start it up and let it idle in driveway. same everytime, except for the restart time. sometimes longer, sometimes shorter. same for the shutdown. sometimes its a short time after start, sometimes it runs a long while. doesnt matter whats on either. ac, heat, wipers, headlights, blower motor, etc. i really have to figure this out.
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Old Dec 1, 2025 | 9:48 PM
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How old is the battery? Maybe it's got something wierd like a cell that shorts out. Really fishing here, but since you lose all power to everything, maybe try another battery from a working vehicle.
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Old Dec 8, 2025 | 5:15 PM
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is there a main crkt breaker like the ones for the windows and accy power? there has to be something between the battery and the main underhood fuse panel. because when it goes. there is still 13 volts at the battery and at the alternator lug, but nothing at the fuse box under the hood, and nothing inside the truck anywhere..
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Old Dec 18, 2025 | 5:15 PM
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ok, i have discovered where the problem is. on the underhood fuse box there are three lugs. one for the wire from the battery to connect to. then two accy lugs. when i check when its running or even not running. there is battery vol;tage avail on all three lugs./ when it shuts off, the voltage on the two accy lugs goes away. i split the fusebox and the buss bars undernieth even loose power when it does the random die. my question is, is there a circuit breaker between the main input lug from the battery to the buss bars? if so, what would be the ampherage of it?
i have figured out how to bypass around it, but i need to know what the max load should be. it has not blown any fuses, so i wouldnt think it should be that high.
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