After 18 years I figured it was time to replace spark plugs on my 05 Colorado.even though it only has 60,000 miles on it. I ordered plugs online from Advance Auto (I guess that`s where I went wrong). Listing said they fit my truck. Put the plugs in and it ran terrible and set off a blinking check engine light. I figured I didn`t have one of the coil wires pushed onto the coil right so I took the air box off again (not as easy as you would think) . Since I couldn`t drive the truck with light flashing I ordered a obd scanner. Connected scanner and it indicated misfire cylinder no.2. Figured it must be bad coil so to verify I switched coil 2 and 3 thinking problem would now be cylinder 3. This time scanner showed misfire cylinder 1. Luckily my adult son had similar problem with his VW suv and told me I had to go to the Chevy dealer to get the right plugs. I was skeptical (especially when I found out the dealers price was 15.80 each and I couldn't find the AC Delco 41-103 plugs for less any where else. Put those plugs in and problem solved. The moral of this story is---when auto parts store webpage says "fits your vehicle" it only means the plugs will screw into the hole.It doesn`t mean they are the right plug.I hope this helps someone avoid the ordeal I just went through.