vmichelle

Car: 2006 IS350 with 135,000 kms (~84k miles).
Recently had the check engine, check VSC, and traction control lights come on and I need some help troubleshooting the problem. Read the code and P0305 came up – Cylinder 5 misfire. Cleared the code and it returned with the next cold start.

First, I changed all of the spark plugs because I didn’t know when they had been done last. I drove around a lot that weekend and the code didn’t return. I then had to go out of town for work – 2 weeks later and over 1,000 kms (~620 miles) I figured the issue had resolved itself. Unfortunately, the next morning it returned.

Next, I changed the coil pack over to a different cylinder to see if the misfire would move with it. I also inspected all of the wires and did not notice any issues. Cleared the code and it returned with the next cold start – same cylinder misfire.

At first when the code came up, I noticed no change to how the car drove. Still smooth, peppy, no hesitation. Once it returned after the first 1,000 kms I noticed the idle was rough (vibrating when stopped). The idle has been getting worse as time goes on (rougher vibrations, and even lurching once I lift off the brake). The moment I give it some gas the car drives as smooth as always.

The issue is the worst in the morning (cold start), after the car has been sitting for several hours but it improves as I drive. If I’m running errands around town and the car is left sitting for only a few minutes or even couple of hours in between stops by the end of the day I don’t even notice any vibrations.

Tomorrow I'm going to swap the spark plug to make sure it isn't faulty, but otherwise I'm looking for any suggestions anyone might have.

MWIS350

Have you taking it to Oreilly Auto part. They will scan for code for free.

vmichelle

I actually own a code reader. In my original post I've stated that the code is a P0305 - cylinder 5 misfire. What I am looking for is some guidance in diagnosing what might be causing this misfire.

(Also, I live in Canada - we don't have O'Reilly Auto Parts up here)

Slammer1

Sounds like you are a smart cookie (I was impressed with you switching coils....). Found this online and would use it as a "flow chart" for diagnosis. I had to do something similar to this on my stepson's Sentra because of a P0505 code even though I had changed the IAC motor..... Unfortunately, the potential issues with the wiring for the circuits can be quite troublesome to track down. Luckily for me the Nissan's issue was a bad ECM. Much easier than rewiring!

http://engine-codes.com/p0305_lexus.html

MWIS350

Does the car feel like it lack of performance. Feel slow?

Gville350

iTrader: (10)

How often do you find yourself hitting WOT in your 350? Perhaps you need to open her open more often to help remove some possible carbon build-up.

When you installed the spark plugs, did you torque to spec AND did you use dielectric grease on the points?

MWIS350

Sometime I like to drive my with ECT PWR mode. You can feel instant power and Wot after 4000RPM.

vmichelle

Thanks for the help. That's exactly the list I already had in my mind. Fuel injectors are probably my next step...as much as I don't want it to be - Any tips on removing them?

Again (in my original post) I stated that the car is just vibrating at idle. Otherwise there is no hesitation.

WOT - all the time
Spark plugs - yes and yes.

WhatYaGot

Did this vehicle have the valve spring recall done already?

vmichelle

Looked up the VIN and the valve spring recall didn't come up (I've only owned the vehicle since Oct). Instead it shows a recall for the fuel pressure sensor gasket. Not sure if this is new or not because I've pulled the recall notices before and nothing came up.


Other updates:
As of this morning I'm now getting P0300, P0303, and P0305 (random/multiple cylinder misfire, cylinder 3 misfire, and cylinder 5 misfire) and the check engine light is now flashing (instead of constant on). The idle is even rougher, but otherwise drives normal. I've stopped driving the vehicle and am currently in the process of pulling the fuel injectors to do a bench test.

Slammer1

Call 1-800-25-LEXUS and give them your VIN. Ask them what recalls are outstanding... Not sure if the valve train recall would contribute to the issue you are having but I would get all required work done by the dealer and then see where you stand with your current problem.

smokyis350

iTrader: (21)

Subscribed. I had a P0303 Cylinder 3 misfire but cleared the code and haven't came back on for a weeks now. Keep us updated.

Gerb

I've had Check VSC and a solid triangle but went away after a bit. Kinda sounds like its a cylinder problem as well as the car feels slower than it use to be. No VSC light as of now. Maybe pops up once every 2 weeks? Maybe I need to change sparkplugs.

MWIS350

Please keep us update if you solved the problem. My IS350 also feel slow, but no code.

Slammer1

I wonder if you don't have an issue with either your camshaft or crankshaft position sensor.... I do believe that one of these being bad could give you a misfire code.