random misfire on 1999 Lexus RX300

dtc 0301 0303 0305 misfire on cyl head # 1 all 3 cyl Always

by in Dallas, TX on September 23, 2010
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1 answer 1 comment
ANSWER by , September 23, 2010
Best to check the basics, i.e do a compression test on the effected cylinders, then if the plugs are old, replace them with factory spec plugs. Also check to see if the coils for each cylinder are contaminated with oil from a leaking valve cover gasket. If so replace the coils as well. These are some of the first steps that I would take to deal with these misfire codes.
COMMENT by , January 20, 2012
Please where are Knock Sensors located? Are they ones at the of top side of Cylinder?