moee

Hi everyone,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:

1. Spark plugs new original Toyota parts.
2. Full tested immaculate condition coils + wires JDM version.
3. Previously 6 months back sockets for coils were changed.
4. Fuel injector’s sockets are in good shape.
5. Fuel injectors one year back were completely cleaned and filters changed.
6. Air and fuel filter are in good condition.
7. Air mass sensor in good condition.
8. No air intake leaks.
9. 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.
10. This step gave me an improvement of %35 but still the misfiring is there.
11. No more misfiring messages but the misfire is still there with less %35.
12. 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.

1. Could it be anywhere in the coils harness ……I mean anybody faced such a thing before.
2. Performance is nice after 2000 rpm. But still I feel the car is clogged somewhere.
3. 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

Mr Jokster

iTrader: (8)

Not sure what you mean "reinsulated" the wires, but first thing i would do is buy new harness for cylinder 3, or cut the wires and solder new ones on and make a complete seal with heat shrink. I believe that 'buzzing' sound you're hearing is spark escaping the wires creating a weak spark at low RPM's in that cylinder only noticeable at low RPM's due to less frequent spark. At faster speeds (in a sense) so much spark is happening that the cylinder basically doesnt see it.

Being that your 'fix' helped a little should impel you to focus on that same area.

lexo98

iTrader: (2)

👍👍👍 while I was thinking about how to reply Jokster handled it

Mcon

iTrader: (1)

Hi Moee and Mr. Jokster,
I just respond your PM Moee and is very funny that I say on your email, contact a Mr. Jokster for a second opinion and I just found this thread. Good luck with that Moee.

moee

Good day every one,First of all I’d like to thank everyone who replied me regarding my ride which shows how much they are giving and helping people they are…..so really thank u.Guys ….see initially the RF- sound (RF-radio frequency-…..like its zzzZZZZZZZ)….it increases with the RPM…………its starts at 2000 rpm ….and rising.Then after few days shaking started …….but randomly. Then two days later it started throwing me codes first it was p0303 which is the center coil misfiring. After I changed the coils with the second handed ones it was giving me code of p0301 which is coil one so I replaced with my old coil front one cause its ok for checking ………….then it turned out ok.NOW…….no codes but the car still shaky and the buzzzzz sound still there……….MY QUESTIONS ARE;

1. Is there any possibility from Ur experiences that the spark cables are shorted like one of them or so as a question like in both sets the newer one and the older one…….i can recognize the difference between them cause the stock ones are black and the newer are blue.
2. The cam shaft sensor I checked and its ok 1275ohms or something usually the chart says 1475 or something …change it.
3. If Ur answer is no to the spark cables then I believe there is a crack in the signal harness which feeds the coils.
4. For this matter shrinking wire is enough to isolate the current or requires more. And from Ur experience where to look for I mean till the oil cap or extend more.
5. Also there lots of wire coming under the front side of the throttle body close to the manifold…..right side of the car………….do I have to inspect those also…….like I’m lost …………..
6. Can u help from Ur experiences Plz…….
   
7. Sorry to bother u guys in this ………..this is the first time I do this in Japanese car usually it’s done in German cars.
8. Besides u might not know……heat in summer here is almost frying ………118 and rising……this yesterday by the way in Dubai.
9. And if insulate the cable shell I insulate the whole thing or just the cracking cause as u know the wires will not be flexible much after re insulating them with shrinking wires.

Plz advice if u have pics I will be grateful………..once again thank u and sorry I can’t reply earlier……too much of work and too much of jumping between far places for work basis.Thanks every one.Wish u the best Moe