i have been owner for 3 yrs now RX300 '00, Here is what is going on first starting to misfire sounding like bomb going on under carage when inspected found to be very hot air coming from area, then quite acting up then few months ago engine light came on this time had it checked saying she is running too lean, and cats are going bad found out 3 of these are in the car! Well some days she will run. Like nothing is wrong then sometimes will not even go past 30mph my guy drilled hole in front cat to let her breath it helped a lot for short while (will plug up hole after fix current issue at hand temp fix we know ) after reading the most common problem is the ECM wth we are on what you all know all to well shoe string budget
Lets back up a little last year was inspection renewal all know this, ok failed inspection not once but 3 times took paperwork to DMV office the man who signs waviers replied that the common problem on this type car is the ECM so we got to thinking maybe find someone willing to rebuild this ECM may solve some of issues at hand but been seeing threads about timing and vvti so I am here to get some advice on where to go from here we love our car..
Already had tuned spark plugs replace and AMF changed and get this knock senors after spending 800. Still running crappy so donned on us maybe its the darn computer module after all so here I am asking for advice.... she has over 230 thousand miles on her I bought her June 2009 @160 thousand want to fix her up because its an good car worth fixing then buying another persons problem....Thank you in advance

 

If, as you say, some days it runs like nothing is wrong, then the problem is not the ECM. Sounds more like an oil control valve problem from what you've described. Relatively inexpensive fix if you do it yourself. If you've already drilled a hole in the cat, can you use it to check for exhaust back-pressure? If your cat is plugged, that would keep the car from going over 30mph.

 

Welcome to Club Lexus!

Are there any CEL's?

 

Thanks for the Welcome! You see we been experiancing this for some time now we had it checked out fixed what the codes its throwing, I will have the oil control valve checked..
I can't remember all the codes, but question stands now if its not the ECM cause sometimes the car itself runs bad, you see when it does run its because rebooting the system after say 50 miles back to running crapy its like the computer itself throwing all kinds of misguided signals to engine luckly haven't backfired since we had knock senors replaced 6 months ago then,car transmission wouldn't go in reverse ugh, after moving the gears by engaging each then it worked that was Jan 1 2013 now very sluggish so therefore suspect the ECM is needing redone now question at hand where is the oil control valve located ?

 

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