Lexus problems rear lift door wont stay up

It sounds like your solonoid is gone.

it sounds like the striker might be out of adjustment, or a spring came loose or broke you can also try spraying some good penetrating oil due to the water that is kicked up from your rear tires will rust up these parts

It can be faulty switch or its issue with lift gate latch.Its got stuck up hard or cracked inside.It has to be inspected.-----------
There are few help links with proper solutions for these problem.I suggest you to refer the links.
Click the link below:----
2007 Mercury Mountaineer: Liftgate will not Unlock or Open? http://whoisbyme.blogspot.in/2012/06/2007-mercury-mountaineer-liftgate-will.html
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Adjust Hydraulic Lifters? http://schematicsdiagram.blogspot.in/2012/04/adjust-hydraulic-lifters.html
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How to open rear lift gate? http://repairhelpcenter.blogspot.com/2011/12/how-to-open-rear-lift-gate.html

--------- Power Liftgate Shuts Down http://whoisbyme.blogspot.in/2012/07/power-liftgate-shuts-down.html
------------ Power Lift Gate Will Not Remain Open http://whoisbyme.blogspot.in/2012/07/power-lift-gate-will-not-remain-open.html
----------- Power Lift-gate will not Operate http://whoisbyme.blogspot.in/2012/07/power-lift-gate-will-not-operate.html
------------- Liftgate will Not Stay Up Open? http://whoisbyme.blogspot.in/2012/07/liftgate-will-not-stay-up-open.html

---------------- Rear Door will not open http://whoisbyme.blogspot.in/2012/07/rear-door-will-not-open.html
------------ 2000 Toyota Corolla: Rear Door wont open from outside or inside? http://whatisbyme.blogspot.in/2012/05/2000-toyota-corolla-rear-door-wont-open.html

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These details will help.
Thanks.

Check out spring housing inside the door lock actuator. I had the same problem, some work anf JB weld will fix it,

ther lift gate gass struts there about 30 to 45 apeace at the part store there the hydrolic lift mrchanisms and a verry common problem if you go to the part stor they will know exactly what you need they are simple to replace pull the clip with a small screw driver or pick then remove and replace

Hi, you need a new pair of lifts. Make sure you get the ones that say rear, as the hood lifts are different. Here is an example: http://www.car-stuff.com/2000lexusrx300liftsupport.htm
The LEXUS ones are pricey.

The gas cylinders props - have a leak They need to be replaced.

On the inside trim, you can remove screws that are by the door handle, arm rest, under door and side of door and then gently pull back on the panel as there will also be retaining clips attached and you don't want to break them. You'll need to lift the door panel upwards in order to get it off the window ledge. Then you'll need to manipulate the panel and disconnect the door handle linkage from the door handle and disconnect the wiring for your controls. Pull back the weather seal and see if you can see the cause. It could be a faulty motor, a bad regulator, jammed guide rail...

Check out the following link, it is a step by step process to getting the fix...
http://www.chefseattle.com/blog/site-news/suburban-rear-liftgate-wont-unlock-how-to-fix/

have the input from the ride height sensor checked, this must be done with a dealer only scanner.