I changed my plugs recently in my 2004 Chevrolet TrailBlazer 4.2l I6 with the coil on plug setup, and now it is misfiring and hesitating when I hit the gas. All the spark plugs have the proper gap and torqued down properly. I tried tightening down the ignition coils and on one I snapped the bolt. Of course my truck is staying parked until I replace the part which I have to order online due to being stationed in Germany with the US Army. The only thing I can think of as far as the misfiring is not having a proper seat with the coils, my question is does anyone have any ideas on how to get a better seating or if there are any other possible issues I could have over looked at all?
What happens when you swap that one original cable/coil back in?
its still the original coils, all i changed where the plugs
The rubber boots with springs in them that connect the plug to the coil can be bad. If you had a NAPA store close by they sell sets of new boots. Not sure how to source them in Germany.
i went and double checked the coils, pulled them off for a short second and all 6 where firing, i will look around and i can order parts online. There is a strip lot on post here but i doubt they would have any trailblazers or envoys. i will look into the springs but i think i do remember when i pulled out the old plugs they where close to a .050 gap whereas the manual i have says they should be a .042, i will be double checking tonight or tomorrow. i will be trying some injector cleaner and check the fuel filter also just to be safe. the vehicle has just over 100,000 miles on it, i want to say 100,400 is about the more accurate number. i do thank every one who has posted and future posts if any. thank you. matt
Other than wondering about that snapped COP bolt (did you seriously overtorque the holding screws?), and suggesting that you verify that your spark plug parts numbers are correct, I have nothing to add…but I do want to offer you sincere thanks for serving our country. i salute you.
yeah i over torqued it but with the other bolts had no issue, guess that one was about to go lol. and thank you
Just asking, but did you compare a new plug to an old one for thread length and tip extension?
i did on that yes, every thing matched up. the particular model plugs called for ac delco 41-981 had been discontinued, so the ones that where the new model replacement ac delco 41-103 where the ones i bought at the post exchange here, and i also did research before purchasing. i think about it now, could a plug itself be bad?