Slight "hesitation" @ 1200 Rpms On Acceleration

[90LS400Lexus]

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!

[SKperformance]

Possibly a cam or crank sensor.

[90LS400Lexus]

Thanks. Should the "check engine" light be illuminated? Its not on when driving. Is there a way to check these sensors?

[aarman4]

Do you feel the hesitation in the accelleration, or is it just a hesitation in the needle only?

[90LS400Lexus]

Do you feel the hesitation in the accelleration, or is it just a hesitation in the needle only?

Both..... <_<

[nc211]

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.

[90LS400Lexus]

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....

[cardona6569]

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

[90LS400Lexus]

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?

[chilkoot]

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.

[90LS400Lexus]

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.

[python]

do what 2rotor would do and dump 5 gallons of 104 octane in it, should clear up any acceleration problems! ;)

[90LS400Lexus]

Aaaaaaaahhhhhhhh. Oh my gosh.

do what 2rotor would do and dump 5 gallons of 104 octane in it, should clear up any acceleration problems! ;)

[python]

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

[90LS400Lexus]

I know... I was quoting something someone at work says all the time to some peoples answers.... lol. :P

[GeeLs400]

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