TurbochargedBull

I worked on my 1992 Lexus ES300 yesterday after reading this post. I investigated the possible spark issue first since it seemed the easiest to verify and I got lucky. I did a round robin with the spark plug wires and disconnected each one at a time until I reached one that upon removing it did not change the idle status. Good spark coming from the distributor but wasn't firing at the head. I pulled the boot and found what had to be a manufacturing defect with the hard plastic insulator. The spark was firing prematurely through a pin hole or crack to the port tube. Of course this means that the spark never reached the combustion chamber which resulted in a dead cylinder. This happened approximately one month after a tune up. The effect was exactly as described in previous post. Shaking at idle and slowly going away as RPM's increase. Loss of power but drivable. However I did not have a check engine light. Perhaps my bulb is also blown. Hope this helps