lenore

here is what a sludged engine can look like after scooping two coffee cans of gunk out.

If you think you have sludge beware, the sludge can starve the engine and the gunk can clog the oil pump screen. I would take the front valve cover off and see if you indeed do have sludge. You absolutely need to know whether your engine has sludge before you proceed. If it does you may have to drop the oil pan and make sure the engine oil pump pickup is clogged. If it is the Oil control valve could be starved of oil pressure and that is why you are getting the intermittant missfires. When the engine is hot the sludge may be moving around causing the problems. If you dont have sludge replace the oil control valve and switch to synthetic. I have found that Castrol oil 0-30 Synthetic European blend really cleans the engine...good luck

Yep absolutely do not do a flush....There is such a thing called fluid exchange where they use the transmission pump to force the fluid through, but most dealerships will not do this because it takes a lot longer than a flush...Do drain and fills and drop the pan and check for excessive metal debris...

Here is all of the info you need. http://us.lexusownersclub.com/forums/index.php?showtopic=7408&hl=iacv

Go to an autozone and get the codes....I suspect the idle air control valve needs cleaning but we really need the correct code that you had.

Your very welcome....

You know Lexus could put trickle chargers on these cars while in the lots....Solar powered even...No excuse for brand new car having these kind of problems...

There is a flex pipe just under the engine oil pan area...Do not take it to lexus unless you want to give money away...Any Muffler shop will weld one in for around $110....THe other place as noted is the gasket between that pipe and the catalytic converter...real cheap part to replace at any reputable shop. see this post on CLub Lexus http://www.clublexus.com/forums/rx-first-generation/350021-exhaust-flex-pipe-issues-2.html

Read my other post about cylinder 2,4,6 which indicates faulty coil firing or camshaft out of time.

I would definetly clean the oil control valve on the camshaft...they are located on the battery end of the engine. one bolt and they come out and can be cleaned....Now the bad news....You may have engine sludge which is causing the Variable valve timing on the camshaft to fail.....This would cause missfires if the camshaft time were way off. I would pull the front valve cover which is easy and take a look....Sludge would look like big gobs of jello or worse.

those codes indicate a bad coil pak....reset the codes and see which one comes up.

No, changed all of my struts and experienced no such thing. Memory steer (yep the old snow job on the customer) that makes me furious. They screwed something up....

You dont have a spare or valet key.? Yes the electronic are in the plastic piece....maybe hold it (plastic piece near steering column while trying other part of key.

Yes the original screen (metal) can be cleaned with a cleaner, but until you have it dropped you dont know if you now have metal or paper....Lexus started using paper a couple of years ago...It is real hard finding the metal screen filter.

First I would not get a flush,,,,we have found many have tranny problems afterwards as it disturbs sediment and pushes it through the valve body. Your mechanic is full of crap....sorry there are no bars on the AWD in the way. I have done this change myself 7 times. here is a post on Club Lexus which shows the entire procedure....I would dump that mechanic in a heartbeat...I dont trust people that lie to me....We suggest multiple fluid drain and fills to get the fluid prestine. Please read this post: http://www.clublexus.com/forums/rx-first-generation/220061-photo-diy-rx300-awd-transmission-fluid-pan-filter-change.html Also the filter is a wire mesh screen in the original transmission. The problem is not the filter but the design of the transmission. Lexus used a very weak design envolving planetary gears mounted in a aluminum carrier...as time goes by the aluminum wears and the gears float, destroying the gears. The fix was a steel carrier with an increase in gears from 4 to 6. The style of driving (city versus freeway) affects these components a great deal...I have seen the poorly designed assembly at a tranny shop locally. His replacement was much more robust. Unfortunately lexus will not tell anyone when the changes were made.

I want to thank all veterans, both current and past for their service to our Country....Please make an effort today to honor veterans for their sacrifices to our country. Shout out your branch of service Mine Navy 1968-1974 here is a great video: http://www.youtube.com/watch_popup?v=KTb6qdPu8JE

dont have your vehicle, but the wood trim is normally mounted with little plastic clips...put some blue masking tape on the edge of both the wood and surround and take a flat screwdriver or putty knife and try to lift carefully the trim between the wood and surround...real scarey the first time around...

I wonder if you have a wire harness or plug connection that is corroaded....I would do so searching there.....a intermittant plug could cause a false count.....See if there is any corrosion inside the plug to the sensors....and trace the harness back to see if it got nicked or damaged...My thought is the cpu is fine.

here is a two part tuturiol best I have seen on utube. Help maybe this should be on sticky's for maintenance thankyou if you see this moderator....

Are there other codes present....(secondary codes.)?

The pump could be part of the problem, But the biggest change I have been told was in the planetary gear assembly. THe original was an aluminum carrier with 4 steel gears while the replacement is a steel carrier with six gears....much stronger design....

I thought there was a recall on the RX400 for white dust being caused by the evaporator core under the dash, maybe the RX350 also had this problem....I would do a search of TSB's and call your local Lexus dealership.... see this thread: http://us.lexusownersclub.com/forums/index.php?showtopic=63537

Here is another wonderful thread from Club Lexus: http://www.clublexus.com/forums/rx-first-generation/220061-photo-diy-rx300-awd-transmission-fluid-pan-filter-change.html Just do not do a flush, Many have had problems afterwards....

I am not sure, but does your car have a Idle air control valve? If so it could cause your symptons...Cleaning it might solve problem. do a search under your forun for IACV valve. Here is the possibility from Club LExus site... http://www.clublexus.com/forums/performance-and-maintenance/529652-random-low-idle.html

Man for that price on fluid I would switch to Amsoil or Mobil 1 synthetic....probably a lot cheaper.