Rough running

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Aug 20, 2019 | 10:01 AM

PatrickBurke

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Rough running

Since i put new plugs into my 91 F250 it has been running really rough and stalls when i come to a stop. I put it on the OBD 1 reader and got codes 18 & 34. I have looked all over and even asked google what these codes meant but havent been able to find out. Also if the plugs are not firing right could that be the cause of the codes?

Aug 20, 2019 | 10:16 AM

Magnum3672

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Did you gap the plugs correctly?

Are all of the wires seated properly?

Are the connections clean of rust and corrosion?

Which engine is it so we can help look for the codes.

Quick Edit.

Found this site with all of the OBD1 Ford 2 digit codes. https://therangerstation.com/tech_li...gitcodes.shtml

Aug 20, 2019 | 10:33 PM

PatrickBurke

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It is the 5.8ltr. The 351 W

Aug 21, 2019 | 07:06 AM

rla2005

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From: Kentucky

It would not be the first time to get a bad plug... As asked before did you verify the plugs were gapped properly? Did you replace the plug wires and/or the cap and rotor as well?

When were the codes displayed? During the Key On Engine Off (KOEO) tests, Stored Code display from Continuous Memory (CM) or when running the Key On Engine Running (KOER) tests.

The code definitions can changed based on when they were displayed. Code 18 is related to the ignition (SPOUT or IDM signal). Code 34 indicates a problem with the EGR valve position. Need to know when the codes were displayed to guide on where to go next.