need help plzzz misfiring low rpm gs300

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Aug 15, 2016 | 12:00 PM

moee

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Driver School Candidate

Joined: Oct 2014

Posts: 11

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From: san diego

need help plzzz misfiring low rpm gs300

Hi guys,I have a gs300-2004 model, run 190,000 miles. I keep it well maintained recently couple a days ago the car started to give misfiring for unknown reasons. The popping is only in small rpms like from 800 to 1500 almost plus minus. This all if u gives a push if u go slowly on it nothing is there sometimes.So I thought maybe plugs r gone ….lets change them especially I didn’t do it long time almost 25000 miles. And check engine light was giving P0303- cylinder 3 misfire. So in brief what I changed periodically:

Spark plugs new original Toyota parts.
Full tested immaculate condition coils + wires JDM version.
Previously 6 months back sockets for coils were changed.
Fuel injector’s sockets are in good shape.
Fuel injectors one year back were completely cleaned and filters changed.
Air and fuel filter are in good condition.
Air mass sensor in good condition.
No air intake leaks.
I have noticed that cylinder-3 connection wire insulations were cracked exactly after the socket for some over twisting or so, so I insulated the two wires from each other completely.
This step gave me an improvement of %35 but still the misfiring is there.
No more misfiring messages but the misfire is still there with less %35.
Before the misfiring starts there was a sound started to generate like a buzzing sound or RF sound like the one you find car radios when three is no sound filters….and still till now…could it be related……but I feel it’s coming from the engine side but after 2500 rpm and it keeps in getter higher with the rpm.

Could it be anywhere in the coils harness ……I mean anybody faced such a thing before.
Performance is nice after 2000 rpm. But still I feel the car is clogged somewhere.
Shall I open the coils harness and re insulate them again or not.

Plz guys anyone have any idea I will be more then grateful to get the thought cause literally this is killing me and making me angry and I’m afraid I will damage the car, besides no power. Plz any help will do and I’m grateful for everyone who read my thread.Very thankful to everyone…….

Moe

Last edited by moee; Aug 15, 2016 at 12:08 PM. Reason: more details