I decided to change spark plugs on my sc400.
I only had a time to change 4 plugs on passenger side motor.
While removing spark plug wires, I damaged #4, #6. The rubber boot and plastic tube fall apart. I carefully put these two wires back into the hole and gave a good pressure to connect spark plug and wire tip. But I think the wire end is just touching the plug instead of tight fit as it supposed to. Maybe it's not connected at all. Parts store was closed when I got to this point, so I just put the bolts back on and started the car. I didn't have any check engine light nor hesistation on idle. I couldn't really tell the difference between before and after I changed 4 plugs.

My questions are:
Will I getting an engine check light if contact between spark plug and wire came loose?
Are there any parts store that sells individual spark plug wire instead of whole set?

I create more problem doing DIY, but I still don't want to take it to mechanic shop.

 

You might start getting some rough idling and misfires sometime down the road so it would be a safe assurance to just replace the wires. A check engine light will come on if the misfire is intermitent enough to affect driving. It will either give a general misfire code or a misfire code on the cylinder(s) that are affected.

For wires check out a lexus dealer. they sell the wires individually, but usually if you replace the spark plugs you want to replace the wires as well. Carson Toyota also sells individual wires.