I need help, my 1998 GS300 has both the Check Engine and VSC lights on. The codes I got are P0300 and P0303. I did some research and found that these codes along with the VSC lights usually means that there's a leak is some vacumn hose some where, or bad spark plugs, or moisture in the gasoline. I took it to a shop, they replaced the spark plugs but the problem is still there. Now they think that it is the fuel injector.

Are they on the right path? They said that there is no vacumn leaks. Please help.

 

I had the once and reset the ecu and it went away! Disconnect your battery and see if it comes back.

 

CL history tells us is most likely due to a Throttle Position Sensor failure. Which should be covered by your powertrain warranty, well if you have a 98, I don't think you're covered or is you have certified pre-owned.

My father just replaced it on a 99 GS300, 60,000 miles.

Do a search on this website, type in "Throttle Position Sensor"

Good Luck.

 

P0300 is the misfire code. This code will show up when ever one or more of the cylinder misfire.
P0303 is misfire on number 3 cylinder. It could be coil pack or spark plug wire or injector( very rare). On the 1998 GS300, your # 3 spark plug got a coil pack sit on top of it and then it will distribute to another cylinder by the spark plug wire.

 

What you want to do is swap the coil pack from 3 to 4 and see if you still have a miss. Otherwise, if you the problem appear on #4. You will know it's the coil pack. I don't see much of these coil pack fail. Also the the wires make there isn't any cut.
JPI

 

how much do these coil packs go for JPI??

 

Johnny, so funny that after I installed the srt last night, my check engine and vsc lights came on...
but after I reset the ecu for twice and it finally go away!
Now the car drives like a monster love these kind of zoom zoom factors!!
Thanks, Johnny!!

 

i have this same problem po300 and po305...i need help!