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Is300 Hesitation

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After living with a hesitation problem for over a year, I found that the problem disappeared after the air flow sensor was replaced. Can this sensor cause hesitation on acceleration or is it just a coincidence?

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my 2001 IS hesitates a lot to accelerate and shifts gears hard. do you think i need new sensors as well.

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While trying to quickly accelerate the car hesitates and sputters. I put top Octane in the car, but still no change. Does anyone have any suggestions; are there any recalls for such a symptom? Lexus ’01 IS300

I seem to be having the same fault. I've yet to try your suggestion, however are you still hesiation free?

Please help, becuase I'm a little *BLEEP*ed with the performace of the car thus far.

:cries:

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How many miles on the car? A friend of mine's IS's fuel pump went and did the same thing. The transmission thing I'm in the process of getting it fixed too, my car actually spins the tires when it shifts up from 2nd to 3rd. Dealer doesn't know what it is so I'm takin it back this week.

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I have a 2003 with the same hesitation problem. Your best bet is to bring it back to the dealer if under warranty. Other than that, the sensors are your best bet, as well as making sure to vary the speed of your car, and make sure to give it plenty of revs from time to time.

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just bought an '01 is300, 50k miles... so i take it that changing air sensor will get rid of that annoying hesitation? if not this, then what does anyone suggest. it is still under warranty and would like to take advantage of it. i am getting tired of getting beat by my buddies lowly !Removed! '98 3series. thanks!

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Try resetting your ECU and then drive kinda hard as much as you can for about 200 miles.

Also you might try cleaning the MAF sensor. Could be just dirty and not getting a good reading. Us some electrical contact cleaner and be real careful not to break the wire.

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Try resetting your ECU and then drive kinda hard as much as you can for about 200 miles.

Also you might try cleaning the MAF sensor.  Could be just dirty and not getting a good reading.  Us some electrical contact cleaner and be real careful not to break the wire.

i called the dealer as i am under warranty and he said these things aren't covered under warranty. honestly, i am not car savvy enough to do those things myself. are those things easy to do? and or how are they done? a quick run down would be appreciated. thanks bartkat!

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Try resetting your ECU and then drive kinda hard as much as you can for about 200 miles.

Also you might try cleaning the MAF sensor.  Could be just dirty and not getting a good reading.  Us some electrical contact cleaner and be real careful not to break the wire.

i called the dealer as i am under warranty and he said these things aren't covered under warranty. honestly, i am not car savvy enough to do those things myself. are those things easy to do? and or how are they done? a quick run down would be appreciated. thanks bartkat!

The technical service bulletins/work is covered under warranty. The shifting problem is covered. It calls for the service department to reflash the ECU.

If you want to try a computer reset just do this.

Open the hood.

Find the battery, next to the firewall on passenger side.

Unbolt the clamp on the negative battery terminal. (the one with the black wire)

Slip the clamp with black wire off the terminal.

Let the car sit for 30 minutes.

Reconnect the negative wire to the battery.

Start the car and go out and drive at varying speeds and acceleration rates for maybe 20 miles.

See if it doesn't run and shift better after that.

(You may have to reset the clock and your radio preset buttons after reconnecting.)

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Try resetting your ECU and then drive kinda hard as much as you can for about 200 miles.

Also you might try cleaning the MAF sensor.  Could be just dirty and not getting a good reading.  Us some electrical contact cleaner and be real careful not to break the wire.

i called the dealer as i am under warranty and he said these things aren't covered under warranty. honestly, i am not car savvy enough to do those things myself. are those things easy to do? and or how are they done? a quick run down would be appreciated. thanks bartkat!

The technical service bulletins/work is covered under warranty. The shifting problem is covered. It calls for the service department to reflash the ECU.

If you want to try a computer reset just do this.

Open the hood.

Find the battery, next to the firewall on passenger side.

Unbolt the clamp on the negative battery terminal. (the one with the black wire)

Slip the clamp with black wire off the terminal.

Let the car sit for 30 minutes.

Reconnect the negative wire to the battery.

Start the car and go out and drive at varying speeds and acceleration rates for maybe 20 miles.

See if it doesn't run and shift better after that.

(You may have to reset the clock and your radio preset buttons after reconnecting.)

dealer said it was only covered up to 50k and that if it needed the ecu upgrade then i am paying. he also said that it is pretty common for lexus's to have this hesitation prob... is this true? what about an air flow sensor? would this help. thanks again bartkat! you the man. i'll give the battery reset a try.

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Try resetting your ECU and then drive kinda hard as much as you can for about 200 miles.

Also you might try cleaning the MAF sensor.  Could be just dirty and not getting a good reading.  Us some electrical contact cleaner and be real careful not to break the wire.

i called the dealer as i am under warranty and he said these things aren't covered under warranty. honestly, i am not car savvy enough to do those things myself. are those things easy to do? and or how are they done? a quick run down would be appreciated. thanks bartkat!

The technical service bulletins/work is covered under warranty. The shifting problem is covered. It calls for the service department to reflash the ECU.

If you want to try a computer reset just do this.

Open the hood.

Find the battery, next to the firewall on passenger side.

Unbolt the clamp on the negative battery terminal. (the one with the black wire)

Slip the clamp with black wire off the terminal.

Let the car sit for 30 minutes.

Reconnect the negative wire to the battery.

Start the car and go out and drive at varying speeds and acceleration rates for maybe 20 miles.

See if it doesn't run and shift better after that.

(You may have to reset the clock and your radio preset buttons after reconnecting.)

dealer said it was only covered up to 50k and that if it needed the ecu upgrade then i am paying. he also said that it is pretty common for lexus's to have this hesitation prob... is this true? what about an air flow sensor? would this help. thanks again bartkat! you the man. i'll give the battery reset a try.

I think the dealer could still do the reflash on the TSB cause there was a recall on that. Maybe try another dealer?

Mine doesn't have a hesitation problem, engine wise. Mine also has a sticker they put under the hood when they did the ECU reflash. However, sometimes under full throttle shifting from 1 to 2 on automatic. It does do better though after I reset the ECU.

As for the MAF cleaning, It's in the intake section right after the air box. You should see the wires coming out of it.

If you just disconnect the tube from the airbox, then spray some electrical contact cleaner around the inside of that fitting, that may be enough to clean the MAF. You just gotta be careful in there because the sensor is just thin metal and easy to break.

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i have the same problem told them about it ...dealer thats how is is...but thanx on the info about ecu up grade...so just go to dealer n tell them this is tsb problem and they will reprogram it under warranty which i do have

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Hello all, I finally FIXED this problem with my '01 IS300. Steve@Lextasy was right, but I have more to add. After some research I found a link that hit the "spot"

1. See this website for the offical RCA:

*Note: I used rubbing alcohol on a Q-Tip, becareful!

http://www.lexusownersclub.co.uk/knowledge...ex_v2&id=50&c=9

2. Like Steve suggested, reset your ECU by disconnecting the battery for 30 mins.

3. Drive the *BLEEP* out of it, once the above is done. As for my '01 IS300

it NOW performs like a new car...wowo! I'm in love with my ride all over again!

4. Then smile!!!!!!

After living with a hesitation problem for over a  year, I found that the problem disappeared after the  air flow sensor was replaced.  Can this sensor cause  hesitation on acceleration or is it just a coincidence?

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Hello all, I finally FIXED this problem with my '01 IS300. Steve@Lextasy was right, but I have more to add. After some research I found a link that hit the "spot"

1. See this website for the offical RCA:

*Note: I used rubbing alcohol on a Q-Tip, becareful!

http://www.lexusownersclub.co.uk/knowledge...ex_v2&id=50&c=9

2. Like Steve suggested, reset your ECU by disconnecting the battery for 30 mins.

3. Drive the *BLEEP* out of it, once the above is done. As for my '01 IS300

it NOW performs like a new car...wowo! I'm in love with my ride all over again!

4. Then smile!!!!!!

Uh, yeah that works. Juts like it says numerous times in this and other threads. :D

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After living with a hesitation problem for over a  year, I found that the problem disappeared after the  air flow sensor was replaced.  Can this sensor cause  hesitation on acceleration or is it just a coincidence?

This is a common problem for all toyota/lexus models that use the Ltype injection. Toyota uses 2 basic types if injection systems, L and K. These are Bosch systems and date back 40 years. The k system utilizes a MAP sensor(manifold absolute pressure). This system recives an "engine load" signal from the map. no load=high manifold vacuum, high load= near 0 vacuum. This along with throtle positon(TPS) readings tell the comuter the appropriate fuel/spark curve to apply.

The L(luft) type injection uses mass air flow. The system is simple but not bullet proof. A "hot"wire lives in the air flow meter along with an air intake temp sensor. Actually 2 hot wires, one for IAT and one for MAF. This sensor sends a 5 volt "hot" signal to the sensor, a ground path, and a reference signal back to the ecu. If the engine is idling then the hot wire will not cool much, the thermistor stays hot and there is a lage voltage drop across the thermistor. The reference signal comes back to the ecu as a low voltage signal=idle. When you romp her down, large volumes of air go past the MAF, cooling the thermistor, alowing more voltage to flow back to the ecu=heavy load. Sounds simple. The problem comes from dust particles adhering to the hot wire not alowing the wire to cool as efficently so the signal back to the ecu is lower voltage=less (percived)load. This can cause a lean hessitation. The problem is worse on cars with high flow oil bath air filters like K&N. Oil molucules stick to the wire and colect dust like a magnet. The sensor wires are very delicate and I DO NOT recomend useing a q-tip. Simply remove the MAF, invert it, and spray brake clean into the MAF. The wire you can see is the IAT wire, but if you look into the plastic housing with a flashlight you will see another wire. This is the MAF signal wire. To remove the MAF, open the hood, leave the key off, find the air filter box, look 5 inches back and you will see a grey wire loom. Depress the tab and disconect harness, use a #2 philips screwdriver to remove the 2 gold screws. Gently lift sensor up and out, spray clean and replace. Dirty MAF can cause a lean hessitation and eventually a P0173 lean fuel trim code. We charge about $100 at the dealership to diagnose and clean dirty MAF's every week. You can now do it for free. Merry Christmas.

Mad Mike 03 IS300 M/T VSQ2 superchaged

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I think what IFixEm is trying to say is that he should clean the MAF sensor. He made it 2 pages long but that's probally what he was trying to say.

IFixEm, it's okay to use a Q-tip and alcohol. I wouldn't use Brake-clean on a MAF sensor...it might damage the sensor.

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I think what IFixEm is trying to say is that he should clean the MAF sensor. He made it 2 pages long but that's probally what he was trying to say.

IFixEm, it's okay to use a Q-tip and alcohol. I wouldn't use Brake-clean on a MAF sensor...it might damage the sensor.

I said "hun" on account of IFixEm made a triple post. :D

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I said "hun" on account of IFixEm made a triple post.  :D

I fixed the triple posting.

I would like to see a pic of that supercharged IS, hint....hint. :whistles:

steviej

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I think what IFixEm is trying to say is that he should clean the MAF sensor. He made it 2 pages long but that's probally what he was trying to say.

IFixEm, it's okay to use a Q-tip and alcohol. I wouldn't use Brake-clean on a MAF sensor...it might damage the sensor.

I did make a tripple post...my bad. Brake clean will not damage the sensor. I have done it every week on customer cars for over 20 years. A q-tip can easily break the sensor wire because it is hard to get it on the MAF wire since you cant see it if the 'tip is in the bore. You can easily see the exposed IAT wire but that is the wrong one. I made it long so people could understand the why not just the how....not everyone is as car savy as you might think.

There also seems to be big confusion between TSB's and campaigns in this board and everywhere on the net. A technical service bulletin is not a recall. Those are called SSC, or special service campaigns. SSC's often apply to all vehicles, not just those under warranty. TSB's just make techs life easier...The soft learn in many toyota tranys is not technically a warranty issue so it is free on toyotas for 3/36 and Lexus for 5/40. If the ecu needs replaced then it is 8/80 coverage. Luckily it is a simple fix....drain the ecu ram via a batt disconect.

Mike

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