I need help. We changed the spark plugs and after we did that, the truck started shaking real bad. So I am wondering, was there something special we were supposed to do before changing the spark plugs to a 2005 Chevy Trailblazer.

 

What kind of plug? Did you check the gap?

 

Well at first we didn't check the gap, because we were under the impression that all spark plugs were already calibrated. Even after we calibrated them it still did the same thing and they were the cheapest brand I don't remember. I just know that they were not AC Delco.

 

did you do 1 plug at a time? you might have mixed up a plug wire if you didnt

 

No plug wires coil over plug. Unless it is a 5.3 I would bet the plugs are wrong. Cheap is never good.

 

good catch MD..never thought of that..

 

What do you mean by "wrong" The wrong kind?

 

What Brand? If it came with Iridium. platinum or double platinum you must use that, you can not use a cheap copper core plug. They may have a listing for it but that does not mean it will work. If the plugs were not at least $6.00 each (probably more) they are wrong. Who makes the plug, what is the part # ?

 

I have same problem I use auto lite and I gap them myself and I kno I did that right but seems like its missin out did it one by one soo I wouldn't mess up but it's jus take a min to get to 40mph I used auto lite brand pllllzzz help asap

 

Put a scan tool on it. I bet you get a "misfire" DTC. Either one of the coils did not seat properly on the plug or you have a bad coil. Also, make sure the connectors on the coil are clean and properly clicked on.