Misfires when hot

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Mar 2, 2024 | 01:30 PM

OlShtBx

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1st Gear

Joined: Mar 2024

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Misfires when hot

1990 F150 300 I6:
I have been getting a hard misfire after the engine gets hot. It’s intermittent, sometimes it will be the moment it gets to operating temp others it after driving for over a hour. It feels like I’m running on 4 cylinders, appears to start absolutely drinking gas, and the whole truck is rattles.

I’ve replaced plugs and wires, fuel filter, and both fuel pumps have been replaced within the last year or so.

Any advice? Thank you in advance.

Mar 2, 2024 | 01:44 PM

Prototypemech

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Joined: Nov 2013

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From: Mojave, Ca

Have you checked for engine codes? Historically, this a common ICM failure, but first step is to check for codes.

Mar 2, 2024 | 01:49 PM

rla2005

Fleet Owner

Joined: Oct 2005

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From: Kentucky

Agreed very common symptoms of a failing Ignition Control Module (ICM) but a failing PIP sensor can do the same thing. Check for codes first.

Mar 2, 2024 | 04:34 PM

AuroraGirl

Lead Driver

Joined: Jun 2021

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Show me a picture of your spark plug wires/plugs/distributor,

And can you show me a picture of your old plugs?? If you dont have that, send a picture of one of your plugs with the wire removed while in the head