I'm in need of some serious help:
So I've had a heck of a time trying to get my 03 Envoy to run properly. I've been experiencing a misfire, when it gets to about 80 km/h and 1500-2000 rpm's the misfire is pretty bad until I accelerate over 2000 rpm and then it runs fine until I fall under 2000 rpm again. I brought the envoy to a shop and they said it was some pedal sensor or something which I paid $300 for the part and labour to have it replaced. Nevertheless the problem didn't go away.
I ended up thinking it might be the spark plugs because they hadn't been changed since I've owned the vehicle. I replaced three of them (cylinders 2,3,4). The threads of the old ones were covered with oil and looked terrible. I had to go somewhere so I planned to do the other three the next day. After installing the 3 the envoy ran better and still had a misfire but not as bad. The next day I installed the other three, one of the plugs had the insulation casing cracked on it. I only realized after pulling the plug out. I looked into the hole and saw the little missing piece sitting over the plug hole. I vacuumed the piece out and I'm pretty sure I got it out. I heard it go through the central vac hose but I couldn't find it in the central vac tank so I don't know what happened. Once I installed those three plugs (cylinders 1,5,6) I started up the envoy and it was bad. It was making a very loud knocking sound and I immediately turned it off thinking I didn't want to do any damage. I tried to start it after that and it wouldn't turn over. Today I turned it to use an OBD II scanner and it started up but still had the very loud knocking. The scanner said there was a misfire in cylinders 4,5, AND 6. I'm completely lost as to why all three would show a misfire considering 5 and 6 at a different time as 4 and the spark plugs are all the same.
I realized tonight after pulling out one of the new spark plugs I got that they are different from the original. The thread is about 1/4" longer and the overall spark plug is 1/4" longer. I looked online and it says this is the right spark plug and the parts store is the one who gave it to me so I'm not sure if this is normal or what. The old spark plugs were AC Delco 41-981 and the new ones I got are Champion 7437.
If anyone knows of what could be the problem please let me know. I would greatly appreciate it.
I just wanted to fix a misfire and thought changing the spark plugs could do no harm but clearly not.
Thanks
So I've had a heck of a time trying to get my 03 Envoy to run properly. I've been experiencing a misfire, when it gets to about 80 km/h and 1500-2000 rpm's the misfire is pretty bad until I accelerate over 2000 rpm and then it runs fine until I fall under 2000 rpm again. I brought the envoy to a shop and they said it was some pedal sensor or something which I paid $300 for the part and labour to have it replaced. Nevertheless the problem didn't go away.
I ended up thinking it might be the spark plugs because they hadn't been changed since I've owned the vehicle. I replaced three of them (cylinders 2,3,4). The threads of the old ones were covered with oil and looked terrible. I had to go somewhere so I planned to do the other three the next day. After installing the 3 the envoy ran better and still had a misfire but not as bad. The next day I installed the other three, one of the plugs had the insulation casing cracked on it. I only realized after pulling the plug out. I looked into the hole and saw the little missing piece sitting over the plug hole. I vacuumed the piece out and I'm pretty sure I got it out. I heard it go through the central vac hose but I couldn't find it in the central vac tank so I don't know what happened. Once I installed those three plugs (cylinders 1,5,6) I started up the envoy and it was bad. It was making a very loud knocking sound and I immediately turned it off thinking I didn't want to do any damage. I tried to start it after that and it wouldn't turn over. Today I turned it to use an OBD II scanner and it started up but still had the very loud knocking. The scanner said there was a misfire in cylinders 4,5, AND 6. I'm completely lost as to why all three would show a misfire considering 5 and 6 at a different time as 4 and the spark plugs are all the same.
I realized tonight after pulling out one of the new spark plugs I got that they are different from the original. The thread is about 1/4" longer and the overall spark plug is 1/4" longer. I looked online and it says this is the right spark plug and the parts store is the one who gave it to me so I'm not sure if this is normal or what. The old spark plugs were AC Delco 41-981 and the new ones I got are Champion 7437.
If anyone knows of what could be the problem please let me know. I would greatly appreciate it.
I just wanted to fix a misfire and thought changing the spark plugs could do no harm but clearly not.
Thanks
