Lexus 27

I have a 93 ES300 with a 3VZ-FE 6 Cylinder (Fed and Canada) engine that has developed an intermittent misfire. It runs ok on start-up, however as the engine warms up, the misfire occurs intermittently and then gets progressively worse to the point where it appears the engine is running on 5 cylinders. The CEL light is not on and when I check for CEL Codes, I get the one-flash-one-pause-one flash, etc., signal indicating there is nothing wrong.

I have purchased new ignition wires, spark plugs, distributor cap, and rotor. However I am hesitant to remove the air intake chamber and the other multitude of peripheral parts required for this installation until I am confident the above parts will solve the problem.

Any thoughts, experience, and/or advice with this problem will be appreciated.

R/
Lexus 27

esucaris1

I had the same problem and the ign wires were the culprit... and as bad as it looks the intake comes off fairly simply the hardest part is the egr pipe and support bracket on the back side of the manifold... I did a engine swap and had the hood off and that made acess to all the bolts on the backside real easy but you can still get to them hood on it just requires more swearing lol... Oh yeah and I almost forgot, "Welcome to CL"

Lexus 27

Thanks esucaris1 for the quick response.

Another question: From your experience, is there adequate access to remove and replace the spark plugs and ignition wires in the back of the engine with the hood removed and without removing the air intake plenum chamber.

R/

Lexus 27

esucaris1

I would not try as it will be next to impossible to route the wires through the wire holders... I have changed the plugs without removing the plenum but the wires are just moved to the side...

Lexus 27

Misfire problem solved! Just as you indicated esucaris1, the wires were the problem. When I pulled the No. 3 Cylinder plug wire, the internal guts of the plug stayed behind on the spark plug. I theorize the internal wire in the plug had cracked. When you started the car cold, the spark was able to bridge the gap in the cracked wire. As the engined warmed, the plug expanded to a point where the spark could no longer jump across the increased wire gap thus causing the pronounced/permanent misfire. When the car cooled down, the cycle would be repeated. With a lot of maneuvering (with mirrors, socket universals/ extensions, long screwdrivers and parts grabbers) I was able to change out all the parts without removing the air intake plenum. Car runs fine now.

Thanks again for all the help

R/
Lexus 27

Infin1ty

A lot of misfire issues today! My engine started doing the same thing this morning. Just like you described, it did not start until the car warmed up. When I took it to the shop for them to fix it though, they said my cylinders 1, 3, and 5 were all misfiring.

Pheonix

change the plugs and wires.





Do not waste time manuvering to do it. Remove the upper intake manifold instead. It takes less than five min to do so Two min tops the second time you do it, and the entire thing needs to be cleaned out as it will be caked with carbon deposites throttle to valves.