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mike switzer
mike switzer,
Category: Lexus
Satisfied Customers: 644
Experience:  lead diagnostic tech at Aamco
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I've got a 2000 lexus gs300 with the check engine light on.

Customer Question

I've got a 2000 lexus gs300 with the check engine light on. Codes are p0300, p0301, p0303, p0305. I have replaced spark plugs, coils, wires, mass air flow, tps. It only happens when warm and under acceleration.
JA: Does the light stay on, or does it blink?
Customer: It blinks then stays on. It picks up misfire in #5 first then the others
JA: What is the make/model of your car?
Customer: 2000 GS300
JA: Are you fixing your GS300 yourself? What have you tried so far?
Customer: Yes, I have replaced the spark plugs (DENSO), wires (denso), Coils, (denso) mass air flow and tps
JA: Anything else you want the mechanic to know before I connect you?
Customer: no
Submitted: 8 months ago.
Category: Lexus
Expert:  david craig replied 8 months ago.

Hi Im David, thanks for visiting the site. those are all you back bank cylinders....interesting. I got to recommend a backpressure test on the exhaust to see if that cat is clogged. and also a compression test on that rear head.

Customer: replied 8 months ago.
It's a straight 6
Customer: replied 8 months ago.
The coils are on #2,4,6 cylinders and wires are on #1, 3, 5
Expert:  david craig replied 8 months ago.

oh crap thinking of toyota 3.0

Customer: replied 8 months ago.
Any ideas?
Customer: replied 8 months ago.
Two exhaust manifolds- 1-2-3 on one and 4-5-6 on other
Expert:  david craig replied 8 months ago.

this is your engine?

Customer: replied 8 months ago.
No, that's a V6, Mine is a 3.0l straight 6
Expert:  david craig replied 8 months ago.

ok, im not familiar with that engine. ill opt out and allow another tech to chime in.

Customer: replied 8 months ago.
The engine is a 2JZGE
Expert:  mike switzer replied 8 months ago.

do the misfires happen all the time or only when warm?

Customer: replied 8 months ago.
Mainly when warm and under medium/ heavy acceleration
Customer: replied 8 months ago.
Also, I have done a compression test on all cylinders and they are good. I have removed the connector for the ECM and noticed a little fluid (like dielectric grease). Cleaned connector with electrical contact spray. Just puzzles me why it's only on odd cylinders.
Expert:  mike switzer replied 8 months ago.

it is how the system works since it only has 3 coils and three wires. when was the last time the wires and boots were done.

Customer: replied 8 months ago.
The wires have been replaced twice , thinking I had a bad set. Cool we're replaced within the last 3 months.
Expert:  mike switzer replied 8 months ago.

what brand do you have also what brand coils what about the plugs?

Expert:  mike switzer replied 8 months ago.

and silly question but are you sure the wires are routed properly from the coils?

Customer: replied 8 months ago.
Denso coils and wires. They are wired correctly as the vehicle runs fine most of the time. Just when I accelerate somewhat hard. I can duplicate the problem when I power brake and stomp on the gas pedal
Customer: replied 8 months ago.
Forgot to mention I also installed new injectors
Expert:  mike switzer replied 8 months ago.

does your check engine light flash

Customer: replied 8 months ago.
I starts misfiring on #5, then moves to #1,#3
Expert:  mike switzer replied 8 months ago.

just to verify what wires are going from which coil to which cylinder

Customer: replied 8 months ago.
2 coil feeds #5 wire, then #6 coil feeds #1, then #4 feeds #3
Expert:  mike switzer replied 8 months ago.

okay i just wanted to verify. it could be a crank sensor causing this as well did it have this issue before or after the changing of the wires and were the plugs done?

Customer: replied 8 months ago.
Before
Customer: replied 8 months ago.
VVT solenoid also replaced.
Expert:  mike switzer replied 8 months ago.

i would start with the crank sensor. and why did you change the vvt solenoid?

Customer: replied 8 months ago.
I had a code set for that early in the year. After replacing the code was cleared. Just wanted to mention all the new stuff
Customer: replied 8 months ago.
I'll try crank sensor, thanks
Expert:  mike switzer replied 8 months ago.

sounds good let me know how things go.

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