95 F-150 Slight Miss

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Mar 14, 2021 | 10:02 PM

jmrule

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95 F-150 Slight Miss

I have a 95 F-150 with a 4.9 I6. It has a slight miss. The number 3 cylinder had a carbon fouled plug. I replaced the cap, rotor, wires and plugs. It runs better and is no longer stumbling at take off but still has a slight miss and smells like it's running rich. I am going to check the timing. Any other ideas on what may be at play? All injectors are clicking at a normal rate and sound fine except number 3 which seemed slightly louder than the others. No check engine light on otherwise. Thanks

Mar 14, 2021 | 10:04 PM

EllieMae94

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From: Mid Missouri

Have you checked the condition of the o2 sensor? It may be overdue for a replacement.

Mar 14, 2021 | 10:20 PM

jmrule

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Good point. This truck is new to me and has over 266K on it. That sounds like a sane place to start. No telling how old it is.

Mar 15, 2021 | 08:25 AM

My4Fordtrucks

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Quote:

Originally Posted by jmrule

No check engine light on otherwise.

That does not necessarily mean no codes.

Mar 15, 2021 | 10:54 AM

jmrule

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Quote:

Originally Posted by My4Fordtrucks

That does not necessarily mean no codes.

Thank you for this. Even the old OBDI will hold codes but no check engine light?

Mar 15, 2021 | 07:49 PM

My4Fordtrucks

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Yes. There could be active and/ or stored codes present. Perform the Key On Engine Off ( KOEO) test. You need to test and repair any faults found before doing the engine running test.

Mar 18, 2021 | 11:35 AM

jmrule

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Ran KOEO and got no codes ran KOER and got code 173 which is O2 sensing that the engine is running rich. This also indicates that the O2 is working. From here I will check timing but beyond that I kindly ask for recommendations on what to check.