At about 50,000 miles I replaced all my spark plugs, just the standard ac delco from the dealership. I drove it for 150 miles and my check engine light came on. So I used my scanner and it said I had a misfire on cylinder one. Apparently my coil on plug went out.

Symptoms:
Check engine light
Very very big hesitation
Hard shifting
Very rough idle


I talked to dealership at the time of the coil replacement and they said that if you replace the spark plugs with something other then ac delco and you have a coil go out then they're gonna send you away. Idk if I was just talking to a complete idiot or what but be careful when replacing spark plugs that are not ac delcos

 

forst off welcome to the site man,

the symptoms would fit a bad coil, but as to why it happened i would have no idea... i actually just sold my extra set of coil packs or i would have offered you mine. check the sale thread for people selling parts you might find some there.

but again i dont think a plug would mess up a pack, but i dont know what would have other then just aging, from not jsut time but the kind of driving your car des

can we get a bump here to help this new member out....

 

Did the TC light come on as well? Cause I'm having the same problem and have yet to pull the code/s (doing this weekend). If not, then it sounds like a bad coil.

 

I just fixed the same problem. The #1 coil plug goes out on a regular basis. One reason it always goes out is because of a loose timing chain. Check the tension on the timing chain. A loose timing chain is very common on the 2.4's.