ok my 97 2.3l work truck loses power after driving for a while, i have changed the cat and it keeps doing it, i also had the codes ran and nothing came up, when i start it in the morning it runs great and is snappy , but about a hour into the day it gets sluggish and when i start from a stop it takes a min to get up to speed,.......

any info would be great

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97 ranger xlt 5spd custom intake 2.3L . Every thing else stock ......
AIM SMALL-HIT SMALL , PROUD TO BE 11B .....HOOAH!!!!!!