Mfss03

Hi Guys,

I hope you guys doing good. I really need help solving my car mystery misfire. I have a 2001 Gs300.

I took it to different mechanics and still can't figure what is going on with the car. this is what I have changes so far to the car and also checked:
1- spark plugs.
2- spark plugs wires.
3- Remanufactured injectors.
3- Compression test "Good"
4- Timing belt Checked.
5- I examined the Vvt solenoid by connecting it to the battery and was moving good.
6- New coils
7- injectors electrical part have been checked too

car is misfiring, hesitate almost everytime I give it a gass except if slowly pressing the gas pedal. The mechanic told me that the misfiring is happening at cylinder 6 and he have no Idea what is wrong with it. the car has codes for random misfire and as I remember all the other cylinders are misfiring too. I will try to scan it this weekend 😅 too.

The last mechanic told me that he needed to check the timing belt which had been changed by another mechanic and would charge me 380 dollars just for checking.

I took the car from the mechanic without checking the timing belt, any suggestion, your help is appreciated it 😊

Mr Jokster

iTrader: (8)

Can you post the codes you got? Thats the only way to get a proper response, or else we're all shooting at the wind.

There shouldnt be any reason to change anything, most parts can be tested. One thing you didnt put on the list are your coils. If you're just getting a misfire on cylinder 6, could be the coil. Testing it is just a matter of swapping it to anther cylinder and seeing if the missfire follows. Could also be an o2 sensor as well.

but first... Codes please .

Mfss03

Thank you, I will try to scan the codes on Friday, and also switching the coil #6 with another one. I have also taken the catalytic converters out 😁, they were blown away too.

I forgot to mention that I got light knocking sound after the misfire has started. it almost took a week for the sound to start after the miafire. I took it to the engine shop and the mechanic said that it looks like a clogged lifter, but told me that the misfire is something else.

KTGS300

Not sure if this will help you but the symptoms you describe sounded exactly what happened to my car after replacing the coils. I had to replace the wire connector to the coil when replacing the coil, they can get brittle and fall apart when taking them out. I removed the wires from the old connectors and put them back in the wrong order on one of them. This caused the car to hesitate when moving from a stop. On my car, the wires were black and black/brown so it wasn't easy to tell them apart. Anyway, after swapping the two wires the hesitation went away. So, check the coil wires going to cylinder #6 and make sure the order matches the other ones. Not sure how easy it is to get to the coil for cylinder #6 since it is all the way in the back. Mine was on cylinder #2 which is up in the front.

brainsurge

Have you checked the MAF? Fuel pump is delivering enough?

kevin3344

One thing you didn't mention was your OCV...common problem on the GS300. As previously mentioned though get the codes first that will help. I wouldn't replace any more parts in hopes of finding a solution. Your codes should narrow down what you need to check.

Mfss03

Thank you all for your time commenting and trying to help me solving this mysterious issue

Just to remind you that I have straight pipes on my car, These are the codes I am getting right now, Just came from Autozone:
P0300 Random Misfire Detected
P0302 Cylinder 2 Misfire Detected
P0303 Cylinder 2 Misfire Detected
P0304 Cylinder 2 Misfire Detected
P0305 Cylinder 2 Misfire Detected
P0306 Cylinder 2 Misfire Detected
P0171 System Too Lean (bank 1 )
P1300 Igniter Circuit Malfunction No. 1

What do you guys think?

The mechanic told me cylinder 6 as i said before, because when he connected the advance scan tool which shows live data for the car, it was showing misfire in cylinder 6.

Mr Jokster

iTrader: (8)

LoL Thats a lot of codes. Very likely you've got an ignition module issue (this is why you post codes first). Something with that many errors in every cylinder isnt going to be any of the fixes you tried. Before thinking about replacing the module, inspect the hell out of the wires on the harness from the module to the coils. Its possible that a rodent got in there and chewed them. Make sure the actual plug is in good condition and lastly, have someone check the module.

Having misfires in every cylinder isnt going to be a single coil, its gonna be something providing the signal to them. However, I have seen 3 coils go out at once though, but very very few times.


EDIT:

I failed to ask an even more important question... When and how did this all happen? Your post makes me assume that you did all those repairs AFTER you got the codes. Did you do a tune up recently, or did all this happen all of a sudden? Were all the repairs done after you had the problem, or before?

Rock-a-Lex

iTrader: (4)

Mfss03

Hi guys, I am sorry I did not reply to your comments. I was just busy working and I have been just using my other car too. but guess what


I went to the junk yard and got couple of used parts for my gs300 just to swap and try, on my way back home I stopped and took a MAF spray cleaner. I cleaned the MAF sensor and

The car is running like a champ

I have just noticed that all the mechanics I took my car to, where just as good mechanically as my 10 months daughter LOoooooooooooooooooooooooooooL


Thanks for everyone.

Mr Jokster

iTrader: (8)

100bajan

iTrader: (12)

I have an 01 430 that is doing this, but I have no check engine light on. It has been doing it off/on for about 2 months now, I reset the ecu and cleaned the throttle body before, and both times it ran better for a few days and then went back to the same thing. There is no particular anything about when it happens, driving slow, driving fast, in the morning or the evening. At times when I start it first thing in the morning the revs go up and down for a little while before it settles.

kevin3344

100bajan check your vacuum hoses and see if any are loose or cracked. I had a fluctuating rpm issue on my '99 GS400 a while back and it was a cracked hose. See photo.

Lk714

100bajan

iTrader: (12)

thanks I'll do that this weekend, funny thing is this morning when I started it up my check engine light came on. One code came up twice P0440.