crossface

What are the symptoms of faulty variable valve timing on a 1999 Lexus GS400? Mine is misfiring, lack of acceleration at speeds of around 45-50 MPH, & when I drop below 20 MPH. It sounds very sick. Just overall very weak. Thinking coil wires & plugs need to be changed, but my mechanic hooked it up & he said the codes never said anything about plugs or coils. He said he thought it was the variable valve timing was off. I do have a suspicion that indeed I need a valve adjustment, but would it affect all that I mentioned?

Wrath

iTrader: (2)

Well what codes were present? Mileage? Need more info to help you,

crossface

I've got to be honest, I wasn't quite clear as to the codes he was explaining to me. I do know that he stated that there was nothing that turned up that involved plug wires or spark plugs or injectors or anything else. I know that's vague & you probably can't go on a lot without that kind of info, but the best way he tried to explain it to me was he thought it was due to the VVT being out of time. He thought it might be that it was low oil compression. But that's just it. I've got no low oil pressure light on the dash. None. I will tell you the car has 277,000 miles on it. I don't know. Perhaps if next time I'm out driving, make a video & upload it. Maybe if you can see firsthand how the car is behaving, maybe that'll be of a little more assistance. I do appreciate you responding to my post. Big help! Thanks.

tiguy99

My wife's RX300 was acting like that. Turns out both OCV valves went bad. About 140 in parts and 160 labor later everything is fine again.

In hindsight I could have done the work myself and saved the 160. Didn't seem like a hard repair at all

eicca

My top suspects would be the oil control valves. You can see them right on top of the timing covers and they're fairly easy to replace.

crossface

You know, after my original post, I started looking around on the forums & found another post where another member was having the same issue. After extensive reading, I'm almost %100 certain that's the issue as well. Not to mention that it's also long overdue for a valve cover gasket replacement. I have a slight leak in the rear driver side valve cover that is causing burn off on my engine block. It's really annoying. Also not to mention that the VSC light stays lit on the dash cluster, which is one of the symptoms the other member was having. Tried stopping by mechanic's shop yesterday to ask him what codes he read. I'm almost certain after my research, it was the all familiar P1349. Anywho, gonna give those a try replacing those & see what happens. Thanks guys, as always you all have been a big help.

D35tr0y312

I also have a 99 GS400 and had the same symptoms and codes last September. misfiring on the passenger side bank and it turned out to be the OCV. I got the replacement part at lexuspartsnow.com and it work great this is the part#: 15330-0F010. Then the other bank OCV failed last month so i had to replace that. I got the replacement from a Toyota dealer. I recommend replacing both at the same time as the the other is only a matter of time.

crossface

Alrightey then. Update time. So I ordered both ocv solenoids & have installed them. Pulled my ECU fuses while doing this procedure, mind you, finished up & replaced the fuse, & started the car. Now the codes still haven't cleared because the VSC lights are still illuminated, check engine light is still on, oh yeah, & now FLASHES while I drive the car. And lastly & more concerning, it has a really rough idle. I'm not talking small rough, I'm saying that at a stop sign with my foot on the brake, the whole car is vibrating. Strange, eh? Once again, any ideas are welcome. I'm at a loss. Thinking I might even put the old solenoid back in. The car ran better & didn't seem like it was running on three cylinders.

eicca

Limp it to an auto parts store and have them write the codes for you. Post them back here.

Also, is the OCV part number the same for both sides?

D35tr0y312

I agree with Eicca, have the codes read. If your OCV was the issue the entire bank will misfire, i.e. Cylinder 1,3,5,7 or cylinder 2,4,6,8. I believe the VVT camshaft position sensors will also cause a misfire. good luck

crossface

Alright. So I figured out why it was running so rough. One of the coil wires came loose from the connector. That fixed that problem. Did run codes & came up with the following:
Lexus Diagnostic Codes
P1346
P0171 System Too Lean (Bank 1)
P1346

HuberNick

bumping for this, my 400 is currently doing the same things, super rough idle, real loss of power for no apparent reason, some days worse then others....
but i am pulling the same exact codes as you are, i feel like the "seal long overdue to be changed" could hold true because my problems started whenever my engine was overfilled with oil..
regardless ive changed the ocv on one bank, and will likely do so for the other now, and today im going to pull my drivers side valve cover off to see whats going on, i will do the passengers side tomorrow hopefully, i will try to keep you updated with results, im at 250k miles right now and would like to get past this little problem so that i can relax for another 30k miles haha