If this is the standard 1ZZFE engine, you have to remove the camshafts after measuring the valve lash to determine the correct lifter (one piece) to replace.
It is also possible the camshaft chain has streached, the teeth on the cam gears are worn.
It is also possible that one or more of the camshafts lobes are worn.
Lifter clearence is relitively simple to check. Remove plastic cover, unplug and remove the 4 coils to the cylinders, remove the camshaft cover.
Rotate each cylinder to firing position and check valve clearence with a feeler gauge.
This must be done when engine is cold.
I would also have the oil pressure checked with a mechanical gauge to make sure it is not a bad/weak oil pump.
Wednesday, March 5th, 2008 AT 5:59 AM