Originally Posted by MX73

It not common on the 2GR-FSE. Lexus added port injection on the 2GR-FSE. It has the best of both worlds. Direct Injection into the cylinder and Port injection in the intake stream. That will wash off the carbon buildup on the back side of the valve.

The 3GR-FSE and the 4GR-FSE only have direct injection.

Originally Posted by Costantine

I have 08 gs350 but I’m not sure if this year have carbon deposits issue ? I’m not really a car expert but if you can give me your experience on that one that would be awesome? Because I get misfire a lot and I been taking care of it and use premium gas all the time and use redline fuel cleaner every 6 month, and I did a tune up recently so not sure what’s going on, thanks again

Originally Posted by Costantine

I do appreciate your fast respond brother, i did change the spark plugs and coils with oem part last year, the problem actually started when I filled up my tank from a different shell gas station I never always get gas from there, I start immediately notice the car shaking and rough idle then while I’m on the freeway I notice the car won’t accelerate good and it didn’t drive smooth as normal, I drive for like 3 days like that then the engine light came with the message check VSC and the skid yellow notification in the dashboard, so what I did I bought a royal purple fuel stabilizer bottle poured in the tank and it does it’s magic the shake/vibrate is gone the idle came Back to normal which is 600/700 then after that on nearly empty tank I used a redline fuel cleaner then I took off my negative terminal on the battery to reset the engine light, after driving it now for 3 days I plugged the OBD scanner and I don’t see any engine light on or any pending codes or whatsoever. Do you think The gas I got from that gas station have water or something that can bring this misfire code ? Thanks again

QUOTE=ibidu1;11224942]The 07-up GS350 do not have carbon issues. It doesnt mean it doesnt happen, of course you will find carbon, but not as bad as the 06 GS300.

As for the misfire, I would take the car to a good mechanic with a good scan tool. A good scan tool will show misfire counts on whatever cylinder that is misfiring, while driving it data logs. Lets say for example cylinder #4 has 600 misfire counts, and the others 0. You can then swap out the ignition coil to another lets say cylinder #2, and the scan tool will show the issue get moved to #2 if the coil was bad. If lets say you swap it and the problem is still there at #4, you can do the same with the spark plug. If that doesnt fix it, then you will need a volt meter and test voltage and signal to that cylinder.

I would take the car asap to have them fix your misfire, if you leave a misfire it may easily allow un-burnt fuel to pass into the exhaust and destroy your cars catalytic converters and that is VERY pricey. Any decent mechanic, no need to take it to the dealer, and it shouldnt take no more then 1 hours worth of diagnostics.

If its a bad coil, I would only replace with oem new, or denso brand. If you are on a budget, pretty sure you can find them used on ebay pretty cheap, as they are not known to go bad.

Originally Posted by MX73

It not common on the 2GR-FSE. Lexus added port injection on the 2GR-FSE. It has the best of both worlds. Direct Injection into the cylinder and Port injection in the intake stream. That will wash off the carbon buildup on the back side of the valve.

The 3GR-FSE and the 4GR-FSE only have direct injection.