90LS400Lexus Posted January 6, 2008 Share Posted January 6, 2008 Hi all. My friend has another problem with her LS. I drove it and when pulling out, when in 1st gear, @ exactly 1200 rpms, there is a light hesitation / jump for less than a second until it gets past 1200 rpms. 1100 is fine and 1300 is fine. Its just that 1200 mark has a "catch" to it so to speak. Does this sound like the throttle body just may need to be cleaned or? Thanks in advance! Quote Link to comment Share on other sites More sharing options...
SKperformance Posted January 6, 2008 Share Posted January 6, 2008 Possibly a cam or crank sensor. Quote Link to comment Share on other sites More sharing options...
90LS400Lexus Posted January 6, 2008 Author Share Posted January 6, 2008 Thanks. Should the "check engine" light be illuminated? Its not on when driving. Is there a way to check these sensors? Quote Link to comment Share on other sites More sharing options...
aarman4 Posted January 6, 2008 Share Posted January 6, 2008 Do you feel the hesitation in the accelleration, or is it just a hesitation in the needle only? Quote Link to comment Share on other sites More sharing options...
90LS400Lexus Posted January 7, 2008 Author Share Posted January 7, 2008 Do you feel the hesitation in the accelleration, or is it just a hesitation in the needle only? Both..... <_< Quote Link to comment Share on other sites More sharing options...
nc211 Posted January 7, 2008 Share Posted January 7, 2008 I'd start with new plugs, then possibly wires, dist. cap. Sounds like a "dead spot" in the spark. Going oem, plugs are probably $60ish? Not sure on wires and caps though. I'm not familiar with the part SK references, not sure how much they cost and labor required to change one out? But, my advice is to start at the easiest point. Since you're doing that, I'd do that throttle body cleaning as well. Quote Link to comment Share on other sites More sharing options...
90LS400Lexus Posted January 8, 2008 Author Share Posted January 8, 2008 I'd start with new plugs, then possibly wires, dist. cap. Sounds like a "dead spot" in the spark. Going oem, plugs are probably $60ish? Not sure on wires and caps though. I'm not familiar with the part SK references, not sure how much they cost and labor required to change one out? But, my advice is to start at the easiest point. Since you're doing that, I'd do that throttle body cleaning as well. Thanks. Its not that bad now, but something I will address sometime this month or next.... Quote Link to comment Share on other sites More sharing options...
cardona6569 Posted February 2, 2008 Share Posted February 2, 2008 After you change the plugs check your engine tranny mounts, that might be the problem if the plugs cable do not resolve the issue. After all it is a 1991, if you have not had them replace by now they are more than due. CPR Quote Link to comment Share on other sites More sharing options...
90LS400Lexus Posted February 8, 2008 Author Share Posted February 8, 2008 After you change the plugs check your engine tranny mounts, that might be the problem if the plugs cable do not resolve the issue. After all it is a 1991, if you have not had them replace by now they are more than due.CPR Thanks I will do that... probably sooner than later. I have noticed that the hesitation is getting slightly worse, but it definitely seems to be the engine and not the tranny. When it hits 1200 rpms, the car will hesitate and the tach will stop at 1200 for a second then pick back up. Seems to be a "dead spot" @ 1200 rpms. Even at speeds, when I hit 1200 rpms, it will hesitate. I am guessing spark plugs and/or plug wires and/or throttle body needs to be cleaned? Quote Link to comment Share on other sites More sharing options...
chilkoot Posted February 8, 2008 Share Posted February 8, 2008 the tranny mount going sour doesn't mean there's anything wrong with the tranny, it just means the connection between it and the engine is not as solid as it could be and the spooling action is not as smooth as it could be. The engine has to spool against the play in the transmission before it can accumulate power, resulting in the hesitation. Quote Link to comment Share on other sites More sharing options...
90LS400Lexus Posted February 10, 2008 Author Share Posted February 10, 2008 Thanks... would this also cause the tachometer (engine speed) to stop at 1200 rpm as well while the hesitation is going on? When the power hesitates, the tach does as well, which is why I was thinking it was engine related. ?? I seems like it is fuel system related, but I have no clue. Maybe I should change out the transmission mount. Thanks for the advice. the tranny mount going sour doesn't mean there's anything wrong with the tranny, it just means the connection between it and the engine is not as solid as it could be and the spooling action is not as smooth as it could be. The engine has to spool against the play in the transmission before it can accumulate power, resulting in the hesitation. Quote Link to comment Share on other sites More sharing options...
python Posted February 11, 2008 Share Posted February 11, 2008 do what 2rotor would do and dump 5 gallons of 104 octane in it, should clear up any acceleration problems! ;) Quote Link to comment Share on other sites More sharing options...
90LS400Lexus Posted February 12, 2008 Author Share Posted February 12, 2008 Aaaaaaaahhhhhhhh. Oh my gosh. do what 2rotor would do and dump 5 gallons of 104 octane in it, should clear up any acceleration problems! ;) Quote Link to comment Share on other sites More sharing options...
python Posted February 12, 2008 Share Posted February 12, 2008 Aaaaaaaahhhhhhhh. Oh my gosh. do what 2rotor would do and dump 5 gallons of 104 octane in it, should clear up any acceleration problems! ;) was kidding Quote Link to comment Share on other sites More sharing options...
90LS400Lexus Posted February 12, 2008 Author Share Posted February 12, 2008 I know... I was quoting something someone at work says all the time to some peoples answers.... lol. :P Quote Link to comment Share on other sites More sharing options...
GeeLs400 Posted November 30, 2019 Share Posted November 30, 2019 Did anyone get issues to this resolved or have a 94 Ls 400 have same problem I changed both ignition coils plugs and wires and had ecm rebuilt still can’t find the problem Quote Link to comment Share on other sites More sharing options...
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