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This same issue is coming up in the GX forum with their 2uz v8’s
I have had 7m, 2jz and 1uz motors do this at start up only to clear up in less than 1 min maybe 10 seconds.
My 1998 GS400 beater with over 340k miles does this once or twice a year, especially after being parked a while .
It always clears up and runs perfect.
Nothing scientific just my personal experience with Toyota cylinder heads. I agree with others that sticking lifter buckets at the valves are the cause; till oil and heat break them loose, then it runs perfect. I do agree that maybe dirty oil MAY have something to do with this...
02 Lexus GS 300 knocking on cold start and when hard acceleration
I have a 2002 Lexus GS 300 that recently I had to get my exhaust replaced cause it was stopped up and the car wouldn’t go any faster then 25mph. I noticed the sound when it started just going 25 when I was taking it home. Got the exhaust fixed and it’s moved now but it does the knocking now in a cold startup and when I stomp it. My oil levels good. My current codes is random misfire and a o2 sensor. Can’t figure out why I keep getting a random misfire but worried about the knocking sound first. Can anyone help? Any suggestions before I just take it to the shop again? Haven’t taken back to the shop cause I’m in a small town and the shop that put my exhaust on also caused a transmission fluid leak next to the exhaust. Also the car sat for like 2-3 weeks when it was waiting for parts. I would start it but in the process my battery died and my altinator went so I stopped starting it till I got the parts. Once I got them the altinator and exhaust was put on and was still doing that.
I have a 2003 GS430, with 71000 miles. During the holidays (and a big East Coast Snow Storm!) I parked my GS430 in my unheated garage, unused for about 8 days. Temps in the garage never fell below about 30 degrees or so - cold, but not THAT cold.
When I started it after it sitting for 8 days, it started right up, but the engine made HORRIBLE knocking sounds and ran VERY roughly for about 30 seconds. After 30 seconds, the knocking gradually disappeared, although a light knocking/tapping sound continued for another 60 seconds or so. I knew the oil was full, and there was NO oil pressure light or Check Engine light, so I let it continue to run. After a couple of minutes, even the light knocking/tapping went away. Never had any lights on the dashboard come on.
It sounded very much like an oil issue. I have owned this car since new, and use Mobil 1 5W-30 EP, with a Mobil 1 filter, which has an anti-drainback valve.
I vaguely remember this happened once before with this car - so this is twice this has happened in 6.5 years of ownership.
After this happened, I changed the oil, since it was due for a change anyway. The oil was not particularly dirty, and I know the engine is clean, as it has used nothing but Mobil 1, changed fairly frequently its entire life.
Was this related to the VVTi? I am a bit surprised that the oil would drain so completely after only 8 days of sitting. The noise really sounded bad - like the engine was self-destructing.
Has anyone had this happen to them? Car runs fine now. Is there anything I need to check? Thanks for any comments...
it's your oil. i has that problem before as well. But once I started using Amsoil 100% full synthetic oil I no longer have that problem after letting my cat sit.
I had similar a few weeks ago. Same scenario, car had been sitting, cool temp and also high humidity. And, it did the same in cool/cold high humidity once many years ago (I live in a generally dry climate) I think the humidity soaks into the electronics and the car has a brain glitch. Not oil problem.
I have a 2002 Lexus GS 300 that recently I had to get my exhaust replaced cause it was stopped up and the car wouldn’t go any faster then 25mph. I noticed the sound when it started just going 25 when I was taking it home. Got the exhaust fixed and it’s moved now but it does the knocking now in a cold startup and when I stomp it. My oil levels good. My current codes is random misfire and a o2 sensor. Can’t figure out why I keep getting a random misfire but worried about the knocking sound first.
The random misfire code is actually probably the knocking your referring too. The random misfire code (P0300) can come from several sources, but if your having any kind of knocking, it’s going to generate a random misfire code. I am not understanding when it starting knocking and how persistent it is now? It got worse when u got the exhaust work done? Or it is just more noticeable now that the engine is revving freely? Does it always sound the same? Or does it get less noticeable at some point? Or is it a consistent knock with the same timing and volume at all times? What was the specific code that came up for the O2 sensors? It wasn’t on when the exhaust was having problems? Did the codes get reset after u got it repaired? Unless u have replaced the O2 sensors in the last 100k miles, I would go ahead do that regardless. If you had a plugged catalytic converter then all the O2 sensors should probably be replaced anyway. They need to be replaced about as frequently as the timing belt. That way u can rule a malfunctioning O2 sensor out. The car will run better with a new set of OEM Denso sensors in the exhaust even if the O2 code persists. Replace em then reset the computer and see if the code comes right back on.
A knock can be a little tougher to diagnose that a misfire. Usually a misfire is a problem in the ignition system but a misfire is more of a fuel or timing problem. Possible worse like a bearing or rod flopping around.
Keep us updated with all the symptoms and we should be able to narrow down the possible causes.
02-03-20, 01:19 PM
