99 Gs300 Intermittent Hesitation When Accelerating

[sfm4103]

Help-I have had 3 Toyota mechanics work on this problem and none can find the problem.

Problem:

Intermittent hesitation (engine misfire or transmission slip?) with normal acceleration, usually between 30 and 50 mph.

Problem does not occur with very light acceleration.

Problem does not occur if I keep transmission in 4th gear instead of drive.

Problem seems to occur more in the afternoon rather than the morning and more often with the AC running (warmer temperatures).

Problem never occurs when engine is cold.

Problem frequency has increased over the past 3 months ago.

95% of the time, the engine, transmission has excellent performance - smooth idle, acceleration, shifting, etc

Mileage:114,000

Replaced plug wires and air filter yesterday - problem still exists

Changed the spark plugs and cleaned the injectors approx. 10,000 miles ago.

Serviced the transmission, replaced timing belt approx. 18,000 miles ago.

Any suggestions will be greatly appreciated

[olddog]

everything you have tried should have eliminated the problem. if it was related to a tune-up issue of some sort.

best advice is to take it to a lexus service centre and have them diagonose the problem.

good luck

[aparker]

Help-I have had 3 Toyota mechanics work on this problem and none can find the problem.

Problem:

Intermittent hesitation (engine misfire or transmission slip?) with normal acceleration, usually between 30 and 50 mph.

Problem does not occur with very light acceleration.

Problem does not occur if I keep transmission in 4th gear instead of drive.

Problem seems to occur more in the afternoon rather than the morning and more often with the AC running (warmer temperatures).

Problem never occurs when engine is cold.

Problem frequency has increased over the past 3 months ago.

95% of the time, the engine, transmission has excellent performance - smooth idle, acceleration, shifting, etc

Mileage:114,000

Replaced plug wires and air filter yesterday - problem still exists

Changed the spark plugs and cleaned the injectors approx. 10,000 miles ago.

Serviced the transmission, replaced timing belt approx. 18,000 miles ago.

Any suggestions will be greatly appreciated

I have a 99 GS 300 also, and I am having the same exact problem. Have you had any luck solving this problem? If so can you provide some insight. Your help would be greatly appreciated.

[menappi]

Fuel filter? Maybe you should run some seafoam through your motor, it works wonders.

[sfm4103]

Help-I have had 3 Toyota mechanics work on this problem and none can find the problem.

Problem:

Intermittent hesitation (engine misfire or transmission slip?) with normal acceleration, usually between 30 and 50 mph.

Problem does not occur with very light acceleration.

Problem does not occur if I keep transmission in 4th gear instead of drive.

Problem seems to occur more in the afternoon rather than the morning and more often with the AC running (warmer temperatures).

Problem never occurs when engine is cold.

Problem frequency has increased over the past 3 months ago.

95% of the time, the engine, transmission has excellent performance - smooth idle, acceleration, shifting, etc

Mileage:114,000

Replaced plug wires and air filter yesterday - problem still exists

Changed the spark plugs and cleaned the injectors approx. 10,000 miles ago.

Serviced the transmission, replaced timing belt approx. 18,000 miles ago.

Any suggestions will be greatly appreciated

I have a 99 GS 300 also, and I am having the same exact problem. Have you had any luck solving this problem? If so can you provide some insight. Your help would be greatly appreciated.

[sfm4103]

No luck yet. I'm going to try a fuel filter next. Problem is getting worse. Turned a corner today and the engine sputtered for approx. 5 seconds and then cleared out and ran fine the rest of the day. I'll let you know if I fix the problem.

[sfm4103]

Fuel filter? Maybe you should run some seafoam through your motor, it works wonders.

I've been told that 99 GS300 has a lifetime fuel filter located in the gas tank located under the back seat. I think I'll replace it anyway and try your Seafoam idea. Thanks for your suggestions.

[aparker]

Fuel filter? Maybe you should run some seafoam through your motor, it works wonders.

I've been told that 99 GS300 has a lifetime fuel filter located in the gas tank located under the back seat. I think I'll replace it anyway and try your Seafoam idea. Thanks for your suggestions.

Ok, please do I am in desperate help! Please do and feel free to email me at ashtonparker@hotmail.com. If I have any luck i'll let you know as well.

[Jrezo]

Does the car have a bad idel as well or just accelration?

I would say fuel, and a filter is ment to stop dirt so its bound to get to the point of being so dirty it needs to be changed. I have not heard of a lifetime filter.

[sfm4103]

Does the car have a bad idel as well or just accelration?

I would say fuel, and a filter is ment to stop dirt so its bound to get to the point of being so dirty it needs to be changed. I have not heard of a lifetime filter.

Idle and acceleration are both good. That's why I wonder if the fuel filter is causing the intermittent hesitation.

[sfm4103]

Fuel filter? Maybe you should run some seafoam through your motor, it works wonders.

I've been told that 99 GS300 has a lifetime fuel filter located in the gas tank located under the back seat. I think I'll replace it anyway and try your Seafoam idea. Thanks for your suggestions.

Ok, please do I am in desperate help! Please do and feel free to email me at ashtonparker@hotmail.com. If I have any luck i'll let you know as well.

OK. I know how aggravated you must be. I know I am. I'm getting close to the point of getting rid of the car if I can't find the problem soon.

[aparker]

Fuel filter? Maybe you should run some seafoam through your motor, it works wonders.

I've been told that 99 GS300 has a lifetime fuel filter located in the gas tank located under the back seat. I think I'll replace it anyway and try your Seafoam idea. Thanks for your suggestions.

Ok, please do I am in desperate help! Please do and feel free to email me at ashtonparker@hotmail.com. If I have any luck i'll let you know as well.

OK. I know how aggravated you must be. I know I am. I'm getting close to the point of getting rid of the car if I can't find the problem soon.

I am the same way; I am about there myself. Do you think I should try and change plugs, wires, and clean injecters or do you think that is a dead end? My car only has 75k miles. I am just fed up! These cars are supposed to last. Let me know if you have any luck with the fuel filter. Thanks.

[Jrezo]

Mass Air Flow Sensor????????

Now that I read all of the problems again this sounds like all of the symptoms.

It does happen once the car is warm and it almost feels like a trans slip. Idle is fine most of the time, harder acceleration like in 2,3,4th gears is when it happens.

The sensor tricks the brain and it thinks its getting to much air to fuel ratio so it cuts the air and it feels like the car wants to die.

You can try to clean it, or test the wires, but I think its best to replace it.

It is the compnent right next to the air filter, very easy to replace and just takes a few minutes. Un-do the two screws and disconnect the wire harness. (ps. might want to disconnect the battery) and Cost $85 and usually a core exchange of $50

Hope this helps. GOOD LUCK

[sfm4103]

Mass Air Flow Sensor????????

Now that I read all of the problems again this sounds like all of the symptoms.

It does happen once the car is warm and it almost feels like a trans slip. Idle is fine most of the time, harder acceleration like in 2,3,4th gears is when it happens.

The sensor tricks the brain and it thinks its getting to much air to fuel ratio so it cuts the air and it feels like the car wants to die.

You can try to clean it, or test the wires, but I think its best to replace it.

It is the compnent right next to the air filter, very easy to replace and just takes a few minutes. Un-do the two screws and disconnect the wire harness. (ps. might want to disconnect the battery) and Cost $85 and usually a core exchange of $50

Hope this helps. GOOD LUCK

I took it out a blew it out. Should I try to clean it with a liquid? If cleaning does not work, I'll replace it. Thanks for your help.

[Jrezo]

Mass Air Flow Sensor????????

Now that I read all of the problems again this sounds like all of the symptoms.

It does happen once the car is warm and it almost feels like a trans slip. Idle is fine most of the time, harder acceleration like in 2,3,4th gears is when it happens.

The sensor tricks the brain and it thinks its getting to much air to fuel ratio so it cuts the air and it feels like the car wants to die.

You can try to clean it, or test the wires, but I think its best to replace it.

It is the compnent right next to the air filter, very easy to replace and just takes a few minutes. Un-do the two screws and disconnect the wire harness. (ps. might want to disconnect the battery) and Cost $85 and usually a core exchange of $50

Hope this helps. GOOD LUCK

I took it out a blew it out. Should I try to clean it with a liquid? If cleaning does not work, I'll replace it. Thanks for your help.

I have heard you can dip it in rubbing alcohal then let it dry. But to be honest its a pretty cheap part so its probably worth it to just get a new one. Might help with MPG as well as performance. I think they sell refurbish ones, if you buy a refurb just make sure it comes with a warranty.

J

[dcfish]

Mass Air Flow Sensor????????

Now that I read all of the problems again this sounds like all of the symptoms.

It does happen once the car is warm and it almost feels like a trans slip. Idle is fine most of the time, harder acceleration like in 2,3,4th gears is when it happens.

The sensor tricks the brain and it thinks its getting to much air to fuel ratio so it cuts the air and it feels like the car wants to die.

You can try to clean it, or test the wires, but I think its best to replace it.

It is the compnent right next to the air filter, very easy to replace and just takes a few minutes. Un-do the two screws and disconnect the wire harness. (ps. might want to disconnect the battery) and Cost $85 and usually a core exchange of $50

Hope this helps. GOOD LUCK

I took it out a blew it out. Should I try to clean it with a liquid? If cleaning does not work, I'll replace it. Thanks for your help.

I have heard you can dip it in rubbing alcohal then let it dry. But to be honest its a pretty cheap part so its probably worth it to just get a new one. Might help with MPG as well as performance. I think they sell refurbish ones, if you buy a refurb just make sure it comes with a warranty.

J

Have you ever reset the ECU ? TPS ?

throttle_position_sensor_GS.pdf

[aparker]

Mass Air Flow Sensor????????

Now that I read all of the problems again this sounds like all of the symptoms.

It does happen once the car is warm and it almost feels like a trans slip. Idle is fine most of the time, harder acceleration like in 2,3,4th gears is when it happens.

The sensor tricks the brain and it thinks its getting to much air to fuel ratio so it cuts the air and it feels like the car wants to die.

You can try to clean it, or test the wires, but I think its best to replace it.

It is the compnent right next to the air filter, very easy to replace and just takes a few minutes. Un-do the two screws and disconnect the wire harness. (ps. might want to disconnect the battery) and Cost $85 and usually a core exchange of $50

Hope this helps. GOOD LUCK

I took it out a blew it out. Should I try to clean it with a liquid? If cleaning does not work, I'll replace it. Thanks for your help.

I have heard you can dip it in rubbing alcohal then let it dry. But to be honest its a pretty cheap part so its probably worth it to just get a new one. Might help with MPG as well as performance. I think they sell refurbish ones, if you buy a refurb just make sure it comes with a warranty.

J

Have you ever reset the ECU ? TPS ?

How do you do that?

[dcfish]

Mass Air Flow Sensor????????

Now that I read all of the problems again this sounds like all of the symptoms.

It does happen once the car is warm and it almost feels like a trans slip. Idle is fine most of the time, harder acceleration like in 2,3,4th gears is when it happens.

The sensor tricks the brain and it thinks its getting to much air to fuel ratio so it cuts the air and it feels like the car wants to die.

You can try to clean it, or test the wires, but I think its best to replace it.

It is the compnent right next to the air filter, very easy to replace and just takes a few minutes. Un-do the two screws and disconnect the wire harness. (ps. might want to disconnect the battery) and Cost $85 and usually a core exchange of $50

Hope this helps. GOOD LUCK

I took it out a blew it out. Should I try to clean it with a liquid? If cleaning does not work, I'll replace it. Thanks for your help.

I have heard you can dip it in rubbing alcohal then let it dry. But to be honest its a pretty cheap part so its probably worth it to just get a new one. Might help with MPG as well as performance. I think they sell refurbish ones, if you buy a refurb just make sure it comes with a warranty.

J

Have you ever reset the ECU ? TPS ?

How do you do that?

Disconnect the neg. battery terminal for 10 min. This will clear all the memory stored and the car will relearn driving habits of the driver. Maybe there is something stored in the ECU that is causing this HICKUP................

[sfm4103]

Mass Air Flow Sensor????????

Now that I read all of the problems again this sounds like all of the symptoms.

It does happen once the car is warm and it almost feels like a trans slip. Idle is fine most of the time, harder acceleration like in 2,3,4th gears is when it happens.

The sensor tricks the brain and it thinks its getting to much air to fuel ratio so it cuts the air and it feels like the car wants to die.

You can try to clean it, or test the wires, but I think its best to replace it.

It is the compnent right next to the air filter, very easy to replace and just takes a few minutes. Un-do the two screws and disconnect the wire harness. (ps. might want to disconnect the battery) and Cost $85 and usually a core exchange of $50

Hope this helps. GOOD LUCK

I took it out a blew it out. Should I try to clean it with a liquid? If cleaning does not work, I'll replace it. Thanks for your help.

I have heard you can dip it in rubbing alcohal then let it dry. But to be honest its a pretty cheap part so its probably worth it to just get a new one. Might help with MPG as well as performance. I think they sell refurbish ones, if you buy a refurb just make sure it comes with a warranty.

J

Have you ever reset the ECU ? TPS ?

How do you do that?

Disconnect the neg. battery terminal for 10 min. This will clear all the memory stored and the car will relearn driving habits of the driver. Maybe there is something stored in the ECU that is causing this HICKUP................

I reset the ECU last week and cleaned the MAF sensor with alcohol last night. Still have the hesitation problem. I plan to replace the MAF next week after vacation

[CarbonGS]

yes, from reading this thread it sounds a lot like a bad mass air flow sensor since it is inermittent. the signal from the air meter only changes as your tps changes. more air = more gas. it could also be coil pack? spark plug?

[sfm4103]

yes, from reading this thread it sounds a lot like a bad mass air flow sensor since it is inermittent. the signal from the air meter only changes as your tps changes. more air = more gas. it could also be coil pack? spark plug?

I've ordered the MAF sensor. What is TPS? Thanks for your info. Hope the MAF works.

[dcfish]

yes, from reading this thread it sounds a lot like a bad mass air flow sensor since it is inermittent. the signal from the air meter only changes as your tps changes. more air = more gas. it could also be coil pack? spark plug?

I've ordered the MAF sensor. What is TPS? Thanks for your info. Hope the MAF works.

Throttle Position Sensor. Check out the .pdf file.

[sfm4103]

Fuel filter? Maybe you should run some seafoam through your motor, it works wonders.

The SeaFoam seems to be helping with the problem, but I still have some left in the tank. It certainly gave me more power. I'll know more once I put more gas in next week without using the SeaFoam. If the SeaFoam doesn't fix it, I plan to replace the MAF sensor. Thanks

[topichka]

when this happens, does it feel as if your accelerator pedal becomes somewhat spongy--like you took your foot off it but didn't? I had a somewhat similar situation and replaced my pedal accelerator assembly and that fixed it...

[aparker]

when this happens, does it feel as if your accelerator pedal becomes somewhat spongy--like you took your foot off it but didn't? I had a somewhat similar situation and replaced my pedal accelerator assembly and that fixed it...

Well, I got so sick of the problem and broke down and took my gs to the dealership for a diagnostics. I should have the source monday. I'll keep everyone posted.