AppleJack Posted November 12, 2007 Share Posted November 12, 2007 After months of trying to find an engine hesitation I have brought the car to a Lexus dealer where their master tech indicated it's not the engine at all. He said it's the lock-up mechnism on the torque converter when I accelerate lightly at highway speeds. You see, when I accelerate at a slight amount without going so far to cause the transmission to kick out of O/D - I get an intermittent jumpiness which is actually the lock-up become disengaged and then engaged randomly. I suspect the lock-up mechanism may be ok and that it may be something controlling this activity ... So my question - Does anyone think some of the sensors involved with the transmission could be the cause of this problem? The manual shows a NO. 1 speed sensor, a NO. 2 speed sensor, and NO. 3 solenoid (for lock-up control and pressure modulation) - any thoughts on which could be related to my problem? There is also a NO. 4 solenoid (for accumulator back pressure modulation)... I'd rather try some "on vehicle repairs" such as spending a few hundred changing sensors or solenoids than let the dealer charge a few thousand changing the torque converter .... thanks for your help.. Quote Link to comment Share on other sites More sharing options...
alicias Posted November 13, 2007 Share Posted November 13, 2007 i think i have a similar problem. its like the engine hiccups or catches its breath. its not the the 02 sensors or the tp sensor because i had those changed. the dealer has never witnessed the car doing this, BTW so they probably think i'm nuts. anyway, i just had the torque converter changed to the one with the higher stall speed. i'm still having the same problem. searching throught the forum, to me, it sounded like the idle control sensor - valve whatever needed cleaning/replacement. i have to ask the dealer the next time i'm there. Quote Link to comment Share on other sites More sharing options...
SKperformance Posted November 14, 2007 Share Posted November 14, 2007 I have a similar problem with my 98 LS where on the highway the slightest increase on the pedal caused the trany to downshift. but it is the transmission reacting to the engine not working efficiently. Rev the engine in increments of 500 rpm's and see if it is a solid vibration you are getting or if the vibration comes and goes. Get some sea foam and dump it in the tank as well as that cleared mine up immediately. Quote Link to comment Share on other sites More sharing options...
BadBob Posted November 14, 2007 Share Posted November 14, 2007 After months of trying to find an engine hesitation I have brought the car to a Lexus dealer where their master tech indicated it's not the engine at all. He said it's the lock-up mechnism on the torque converter when I accelerate lightly at highway speeds. You see, when I accelerate at a slight amount without going so far to cause the transmission to kick out of O/D - I get an intermittent jumpiness which is actually the lock-up become disengaged and then engaged randomly. I suspect the lock-up mechanism may be ok and that it may be something controlling this activity ...So my question - Does anyone think some of the sensors involved with the transmission could be the cause of this problem? The manual shows a NO. 1 speed sensor, a NO. 2 speed sensor, and NO. 3 solenoid (for lock-up control and pressure modulation) - any thoughts on which could be related to my problem? There is also a NO. 4 solenoid (for accumulator back pressure modulation)... I'd rather try some "on vehicle repairs" such as spending a few hundred changing sensors or solenoids than let the dealer charge a few thousand changing the torque converter .... thanks for your help.. I have had a similar problem. All the sensors checked out. I read that a valve in the tranny may be stuck. I drained the tranny, cleaned the screen, refilled with Seafoam tranny flush & A/T fluid, shifted thru all gears at an idle, ran the car for 5 miles. Repeated the above. Drained the tranny, cleaned the screen & filled with A/T fluid. Problem corrected. Quote Link to comment Share on other sites More sharing options...
AppleJack Posted November 16, 2007 Author Share Posted November 16, 2007 Seafoam - sounds like a nickname - what is the product make up and application? tranny or fuel tank??? I've been dropping 2 litres from the tranny and topping back up - and I do this about 1 x per year ... Doesn't show any error codes... Quote Link to comment Share on other sites More sharing options...
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