Anyone Experienced Jerk Motion

[chubyball]

Does anyone here experience a jerk motion when let's go the gas pedal? This problem is rarely happening. I can not dupplicate the problem right after this happened. After this problem happening now I got an error code P0430. If someone had a similar problem, please give me some advices how to solve my problem. Thanks!

[99lsguy]

Chuby,

P0430

Catalyst System Efficiency Below Threshold Bank 2

99

[chubyball]

I went to Advance Auto and told them the part that I need for code P0430 and he said it's too general. He gives me a number of a shop where can diagnostic and tell exact problem with which item is bad. The labor will be $32.00 anyone have any suggestion? Should I went and waist 32 bucks for diagnostic?

[99lsguy]

Check out my pdf file in the thread....its example for 99 LS

torque convert /tranny acting up by SC

Chuby,

put your - Model year & LS w/mileage on your info - for all to see

[kubys]

99LSguy,

I don't understand where you are suggesting to look for the PDF file. Can you please post a link?? I appreciate the help. My car is doing the same thing. BTW, mine is a '95 LS w/ 123k.

kubys

[VMF]

yeah it is too general, you just have to troubleshoot a lil bit deeper to get to the part that exactly gives you the problem.

here is what the manual said:

CIRCUIT DESCRIPTION

The ECM compares the waveform of the oxygen sensor located before the catalyst with the waveform of the oxygen sensor located after the catalyst to determine whether or not catalyst performance has deteriorated.

Air-fuel ratio feedback compensation keeps the waveform of the oxygen sensor before the catalyst repeatedly changing back and forth from rich to lean.

If the catalyst is functioning normally, the waveform of the oxygen sensor after the catalyst switches back and forth between rich and lean much more slowly than the waveform of the oxygen sensor before the catalyst.

But when both waveforms change at a similar rate, it indicates that catalyst performance has deteriorated

[VMF]

here is the description of the error

[VMF]

DETECTING CONDITION

CONFIRMATION ENGINE RACING PATTERN

[VMF]

1) Connect LEXUS hand-held tester to DLC3, or connect probe of oscilloscope between terminals OXL1, OXL2, OXR1, OXR2 and E1 of ECM.

(2) Start engine and warm it up with all accessories switched OFF until water temperature is stable.

(3) Race engine at 2,500 3,000 rpm for about 3 minutes.

(4) After confirming that waveforms of heated oxygen sensors bank 1, 2 sensor 1 (OXL1, OXR2), oscillate around 0.5 V during feedback to ECM, check waveform of heated oxygen sensors bank 1, 2 sensor 2 (OXL2, OXR2).

HINT: If there is a malfunction in system, waveform of heated oxygen sensors bank 1, 2 sensor 2 (OXL2, OXR2) is almost same as that of heated oxygen sensors bank 1, 2 sensor 1 (OXL1, OXR1) as shown.

There are some cases where, even though a malfunction exists, MIL may either light up or not light up.

[VMF]

here is what you do next

[VMF]

and then this :)

(i just have to write smth to do the post, but the main info is in the pic:))

[VMF]

forgot to attach the pic

oops

but here it is

[kubys]

Thanks a bunch, VMF. Sounds like it's either 1 of the oxygen sensors or the catalytic converter. Great detailed information.

kubys

[99lsguy]

99LSguy,

I don't understand where you are suggesting to look for the PDF file. Can you please post a link?? I appreciate the help. My car is doing the same thing. BTW, mine is a '95 LS w/ 123k.

kubys

Kubys,

Sorry I left you hangin there...did VMF fix you up?

Let me know if I can be of further help....

99

[kubys]

99lsguy,

Looks like he gave me some real good direction. Do you have anything else to add????? Sounds like it's more than likely an O2 sensor. Is there one that usually goes out first?? I don't have any check engine lights on or anything like that. I just experience the "herky jerky" motion once in a while. I appreciate everyone's help on the board!!!!

kubys

[VMF]

yeah, you are not the first one who have this problem, i gave it to couple of people already. somehow sensor1 on bank2 usually goes out first.

[99lsguy]

Kuby's,

Here's a diagram of their locations:

I think I can find what VMF gave you in one file for conveinience (sp)...

comp.pdf

[99lsguy]

Kubys,

All the stuff VMF has in PDF....

cip0420p.pdf

[kubys]

Thanks a ton for the assistance!!!!

kubys

[chubyball]

Thanks to everyone. Special Kubys, who continue pursue the problem. Cheers :)

By the way, my LS400 '95 milleage is 134K

[BlackSC4]

have you guys solved the problem? here's extra ideas to add to the list:

check the throttle position sensor, last time i played around with that, i got jerky motions. try not to set it too low since at higher rpms, ul starve of air. <---also cause your mpg to go waaaaay down, so check that too.

is it the right fuel cap? some are vacuum, vented, and nonvented <---there's a difference.

[dfaulkner]

Does anyone here experience a jerk motion when let's go the gas pedal? This problem is rarely happening. I can not dupplicate the problem right after this happened. After this problem happening now I got an error code P0430. If someone had a similar problem, please give me some advices how to solve my problem. Thanks!

I have experienced the same problem, also my car on ocassion would die after extended driving. Lexus could duplicate either problem.

A mechanic said he thought it was the ECU. I replaced the unit with a remanufactured unit. Solved both problems. 95 LS400 115,000 miles

dfaulkner

[srgilbert]

Hi,

I have a 95 with similar problems - jerking at particular speeds. The plugs wer replaced, the TPS replaced and Lexus wants several hours to rule out possibly a fuel pump or bad EGR before offering relief on a replacement ECM (perhaps $300 in labor before relief) . I'm about ready to purchase a bone yard ECM for about $150 with the correct vintages posted earlire. If anone else has suggestions please let me know.