truck runs really rough then found a couple bad spark plug wires so changed them ran a little better but still doesnt run as it should. I also changed the fuel pump, cap, and plugs but no change. I also cant get the check engine light to come on but it will not. The knock sensor has also been changed . Any help would be appreciated.Thanks

???? It's older now of course. Perhaps a compression test is in order,

T
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Tom Greenleaf - MetroWest, Boston