Originally Posted by fudge0514

I just did mine last week (just got my truck in May). Previous owners broke a few of the black outer clips, and all but 3 of the red plastic clips were missing. I broke two of the black clips myself (man they were fragile). The harnesses still go in, and the engine seems to be running just fine still. No engine light or codes. I would assume if even one of the harnesses wasn't connected firmly enough and wasn't making power I might get a check engine light, but I don't know. Does seem like my mpg dropped about 1/2 to 1 mpg since doing the plug swap.*

Wonder if I should get 8 all new plug harness connectors? I wonder if the outer portion of the connector is replacable? (If the black outer piece connected to the harness comes off and I can put new ones on easily I'd like to do that).

*Edit - Hard to say for sure as this was only after two half fill ups. Weather got very cold and windy and that certainly affected mpgs. Also did more city driving this past week than I usually do.

Originally Posted by XMP64

Give your truck some time to relearn the fuel/air/spark ratios. I'd give it a another week or so and then see how you feel. You can order those clips from A1 auto, Amazon or the stealer, but those don't come off once plugged in unless something in the motor bay tugs on the wires.
If you can find the new clamps/clips at a decent price I'd go ahead and grab them. I have one broke but I'm not worried about it.