LMSeal Posted April 22, 2018 Share Posted April 22, 2018 Need help here, all else has failed including $150 trip to the stealer. 2009 Lexus RX350 3.5L throwing codes P0300 (multiple random misfires), P0302 (misfire on cylinder 2), P0304 (misfire on cylinder 4). Changed all spark plugs; replaced injectors on 2 and 4; replaced coils on 2, 4 and 6; changed camshaft position sensor in middle of bank 2. When the vehicle is warmed up for 20 minutes it won’t throw the light but tester is still showing codes. Oil consumption has increased slightly and there is excessive crankcase smoke when the oil cap is removed. Stealership tested engine and vacuum test indicated internal engine failure. They are telling me either broke ring or bent valve. This engine has NEVER been overheated. I find it highly unlikely that two piston rings would break in cylinders side by side, or the same for valve stems bending. Considered blown head gasket, but there is no water or coolant in the oil. When the CE light is on steady it runs fine, when it blinks it runs bad. VSC light also blinks. Sorry for the lengthy post, I’ve tried everything I could think of. Now I need somebody in the know to think for me. Advance thanks for your help! Larry Quote Link to comment Share on other sites More sharing options...
RX400h Posted April 23, 2018 Share Posted April 23, 2018 How many miles are on the odometer? If piston rings are broken or a valve stem is bent, you either have over 300,000 miles on the odometer or there is a factory component defect. Remember that not all dealerships offer equivalent technical expertise. You might consider taking your vehicle to the largest dealership in your area. By the way, if your PCV valve is stuck. crankcase pressure may build up enough to cause issues, although I would think that it is uncommon for most vehicles with under 150,000 miles. Quote Link to comment Share on other sites More sharing options...
2ndRX Posted April 23, 2018 Share Posted April 23, 2018 Where are you located in Florida? I know of an excellent independent Lexus mechanic in Naples. Quote Link to comment Share on other sites More sharing options...
LMSeal Posted April 23, 2018 Author Share Posted April 23, 2018 RX400h I did change PCV valve when I changed all the other stuff, forgot to mention that. Vehicle has 190K miles. I took it to Lexus of Mobile (AL) as there are not a lot of Lexus dealers around here, others are 3 hours away I think. 2ndRX, I am in Navarre near Pensacola, Naples is a long haul for me. Thank you both for your replies. Quote Link to comment Share on other sites More sharing options...
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