October 30: LEMON manuals on a temporary server, it is slow and having issues, download the manuals you need! Later in November we will switch back to the fast server.

Spark Plug Check

Faulty or fouled plugs may perform well at idle speed, but at higher engine speeds, they frequently fail. Faulty plug can exhibit the following symptomes:

Poor fuel economy.
Power loss.
Decreased engine speed.
Hard starting.
Generally poor performance.

Spark plugs also malfunction due to carbon fouling, excessive electrode air gap, or broken insulators.