93 Es300 With 193k Lurches

[bhasu]

Hi all,

I have a 93 ES300 that has been lurching quite roughly when put on drive. It does not happen when it is on reverse or neutral or Park. It only happens when the engine is cold and on drive. Most of the time, the pulsating stops after about 3 - 5 surges and the engine smoothens out. Sometimes it only pulsates once or twice when I give it more gas.

I have scoured different forums and found some information on this, but for most people it seems to happen when the engine is at operating temperature after getting off the freeway with a hot engine. Mine is exactly the opposite scenario.

Has anyone seen this problem? Or for that matter anyone else has an idea on this. It has 193K in it and still drives very well. But this problem is starting to scare me.

Before going on a wild goose chase, I would like to know if someone has nailed the cause of this issue.

Please me if you have any ideas on this.

Regards.

[Toysrme]

I'd start with cleaning the IAC, Throttlebody & EGR

Check the throttle valve (kick-down) cable is in adjustment

CHeck transmission fluid

Check that the engine mounts are ok

[bhasu]

Thanks for your quick answer. I was going to clean the IAC first. Being someone who has basically done no work on my vehicle and being a wannabe DIYer, I had my coworker show me where the TB, EGR and the IAC are and what they are meant for. When he was explaining these different things to me and showing me how to do the cleaning, we noticed that one of the vaccum tubes was cracked.

I want to do this one thing at a time to find out exactly what it causing the problem. So I am going to change these vaccum cables first today and go clean the IAC and throttle body next. I will keep you guys posted on my progress/lack of....

Thanks.

I'd start with cleaning the IAC, Throttlebody & EGR

Check the throttle valve (kick-down) cable is in adjustment

CHeck transmission fluid

Check that the engine mounts are ok

[Toysrme]

Sounds good.

A vacuum leak could cause the stalling & poor running at low throttle too. If it gets better after u fix the split hose, there ya go! (But ya still may wanna clean the above mentioned things.)

[bhasu]

Sounds good.

A vacuum leak could cause the stalling & poor running at low throttle too. If it gets better after u fix the split hose, there ya go! (But ya still may wanna clean the above mentioned things.)

Changed the hoses and the problem still remains...... Next, I will clean the throttle body and the IAC. Will keep you posted.

[bhasu]

Toysrme,

I found some instructions on cleaning the TB and the IAC valve in the following thread:

http://us.lexusownersclub.com/forums/index...ac+instructions.

The links to the pictures were broken on it. So I don't have any instructions on how to do it.

I am planning unhooking the intake hose from the TB, clean the TB and the TB plate with a carburator cleaner and a brush. Next, I plan on then taking the coil on top of the IAC valve out, and cleaning the IACV. I am not sure how to clean the EGR. Do I just loosen the three bolts that hook the EGR to the engine, take it out and and clean it with carburator cleaner?

If anyone could give me instructions and tell me what I need to be careful about, I would appreciate it.

Thanks.

[mrbutz1]

Toysrme,

I found some instructions on cleaning the TB and the IAC valve in the following thread:

http://us.lexusownersclub.com/forums/index...ac+instructions.

The links to the pictures were broken on it. So I don't have any instructions on how to do it.

I am planning unhooking the intake hose from the TB, clean the TB and the TB plate with a carburator cleaner and a brush. Next, I plan on then taking the coil on top of the IAC valve out, and cleaning the IACV. I am not sure how to clean the EGR. Do I just loosen the three bolts that hook the EGR to the engine, take it out and and clean it with carburator cleaner?

If anyone could give me instructions and tell me what I need to be careful about, I would appreciate it.

Thanks.

And a quick add on to that question...is the EGR situated the same on a 94 as a 93? Thanks.

[bhasu]

I just had an idea.

If it was the IAC valve that was not functioning properly, I would get a rough idle. My idle is silky smooth. My peoplem of lurching only happens when the gas pedal is pushed softly in a cold start. It is happening more and more in non-cold starts too now. I am thinking that it is being caused by the carbon buildup in the throttle body in a way that the carbon impedes the movement of the throttle plate when it is pushed slightly. The carbon buildup probably is less-bad in other areas of the throttle body and hence the running is smooth.

Any thoughts??????

[mrbutz1]

I just had an idea.

If it was the IAC valve that was not functioning properly, I would get a rough idle. My idle is silky smooth. My peoplem of lurching only happens when the gas pedal is pushed softly in a cold start. It is happening more and more in non-cold starts too now. I am thinking that it is being caused by the carbon buildup in the throttle body in a way that the carbon impedes the movement of the throttle plate when it is pushed slightly. The carbon buildup probably is less-bad in other areas of the throttle body and hence the running is smooth.

Any thoughts??????

I took the excllent advice of several here, including Toys and SK, and cleaned the MAF and TB a couple weeks ago myself with some carb cleaner, isopropanol, a Q-tip and a toothbrush and found increased acceleration, though no improvement in mpg. I recommend it, and it's easy, just don't break the MAF wires...be careful with the Q-tip. I did not remove the TB itself, so did not clean the IAC.

[bhasu]

Thanks for your replies and PMs.

I started cleaning the TB today only to notice that there is some carbon buildup on the inside of the throttle plate, but that the throttlebody is quite clean. Since I did not have the time to clean up the IAC valve, I decided to put the air intake tube back in and head back to work. Guess what? The idling was terribly rough all of a sudden.

Since the only thing I had done anything to was the air intake tube running from the air filter to the throttle body, I was amazed at how this could have suddenly occured. After a careful look, I noticed that this pipe had several cracks on it. I closed the cracks with my fingers and heard the engine smoothen out. So I put some duct tape where the tube was cracked and it ran smoother than I ever remember. Acceleration from a full stop was better than I ever remember (it had 143K on it when I bought the car) and I noticed absolutely no lurching. Granted, the lurching happens more frequently when the engine is cold, but I tried some of the other usual things that seem to cause the lurching more and more often, and still no lurching. Plus, I am enjoying the additional gain in acceleration.

I think the TB does not need any cleaning yet. But I am going to try some of the seafoam solutions I found on other threads. Thanks for all your help. And yes, I am going to install a new tube.

[xxbulovax91xx]

Read my post about 2 down below yours about "MAJOR ISSUES WITH MY 95 ES300".. Sounds like we're having similair problems. Is your check engine light on?