2001 Toyota Echo P0301

Should lead you to check the sparkplug,compression and injector for no. 1

Should you have to keep your mechanic honest leads me to believe that you dont trust him / her. If I was following this problem, first thing I would look at is the spark plugs, check to see if they are cracked. I would also suspect that the coil may have been damaged. If the spark plug is cracked, you may have burned out the coil causing a misfire. to find out, clear the codes, switch the coil with another known good one and see if the code jumps to p0302than (cylinder 2 misfire). My money would be on a bad coil and is much cheaper to do than replace an engine for a compression problem.