99 Gs300 Intermittent Hesitation When Accelerating

[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.

After $150 of diagnostics at the lexus dealership, they came up with a clogged catalytic converter. The car was sent to an exhaust specialist and they did temperature readings of the inlet and outlet of the catalytic converter and found that one was clogged. Now, here is the bad news...really bad news, the converters are part of the entire exhaust manifold so in order to replace the converters one would need to replace the whole assembly and an assembly from Lexus is $900 and installation and other parts total up to $1400. On the other hand, you can cut out these converters and weld one in its place. If you took this route, depending on who you went to, would cost roughly $600. There you go. I'll let everyone know if this works.

[sfm4103]

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.

After $150 of diagnostics at the lexus dealership, they came up with a clogged catalytic converter. The car was sent to an exhaust specialist and they did temperature readings of the inlet and outlet of the catalytic converter and found that one was clogged. Now, here is the bad news...really bad news, the converters are part of the entire exhaust manifold so in order to replace the converters one would need to replace the whole assembly and an assembly from Lexus is $900 and installation and other parts total up to $1400. On the other hand, you can cut out these converters and weld one in its place. If you took this route, depending on who you went to, would cost roughly $600. There you go. I'll let everyone know if this works.

Sorry to hear about the $ you're having to spend, but I guess it will be worth it if it fixes the problem. It's cheaper than trading cars!!!! I'm not a mechanic, but it seems like you would have constant performance problems instead of intermittent it the CC was clogged.

Update on my SeaFoam try. I'm now on my third day without SeaFoam in my tank and the hesitation problem has not occurred once and performance is better. The jury is still out, but so far so good. I'll let you know the results in a couple of days.

[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.

After $150 of diagnostics at the lexus dealership, they came up with a clogged catalytic converter. The car was sent to an exhaust specialist and they did temperature readings of the inlet and outlet of the catalytic converter and found that one was clogged. Now, here is the bad news...really bad news, the converters are part of the entire exhaust manifold so in order to replace the converters one would need to replace the whole assembly and an assembly from Lexus is $900 and installation and other parts total up to $1400. On the other hand, you can cut out these converters and weld one in its place. If you took this route, depending on who you went to, would cost roughly $600. There you go. I'll let everyone know if this works.

Sorry to hear about the $ you're having to spend, but I guess it will be worth it if it fixes the problem. It's cheaper than trading cars!!!! I'm not a mechanic, but it seems like you would have constant performance problems instead of intermittent it the CC was clogged.

Update on my SeaFoam try. I'm now on my third day without SeaFoam in my tank and the hesitation problem has not occurred once and performance is better. The jury is still out, but so far so good. I'll let you know the results in a couple of days.

Where do you get seafoam and do you just add it to the tank? I want to try it before I go and spend money on new converters.

[sfm4103]

I bought SeaFoam at NAPA for approx. $ 7.50. You can also get it at most Pep Boys and Auto Zones. Add a full can to a full tank of fuel. Check out their website at www.seafoamsales.com. I drove 100 miles today and still no hesitation.

[sfm4103]

I bought SeaFoam at NAPA for approx. $ 7.50. You can also get it at most Pep Boys and Auto Zones. Add a full can to a full tank of fuel. Check out their website at www.seafoamsales.com. I drove 100 miles today and still no hesitation.

Looks like Seafoam fixed my hesitation problem. No hesitation in 1.5 weeks. Thanks to everyone that made suggestions and especially to Menappi for his Seafoam suggestion. He saved me a ton of money and aggravation. Thanks.

[aparker]

I bought SeaFoam at NAPA for approx. $ 7.50. You can also get it at most Pep Boys and Auto Zones. Add a full can to a full tank of fuel. Check out their website at www.seafoamsales.com. I drove 100 miles today and still no hesitation.

Looks like Seafoam fixed my hesitation problem. No hesitation in 1.5 weeks. Thanks to everyone that made suggestions and especially to Menappi for his Seafoam suggestion. He saved me a ton of money and aggravation. Thanks.

Have you had any hesitation since??? Lexus diagnosed mine with clogged catalytic converters; howver, that didn't fix the problem. So they replaced the wires and the coil packs. This solved the problem. So if you still have the problem this might be a place to look. The symptoms you described were identical to mine, but they are gone now. FINALLY!

[sfm4103]

I bought SeaFoam at NAPA for approx. $ 7.50. You can also get it at most Pep Boys and Auto Zones. Add a full can to a full tank of fuel. Check out their website at www.seafoamsales.com. I drove 100 miles today and still no hesitation.

Looks like Seafoam fixed my hesitation problem. No hesitation in 1.5 weeks. Thanks to everyone that made suggestions and especially to Menappi for his Seafoam suggestion. He saved me a ton of money and aggravation. Thanks.

Have you had any hesitation since??? Lexus diagnosed mine with clogged catalytic converters; howver, that didn't fix the problem. So they replaced the wires and the coil packs. This solved the problem. So if you still have the problem this might be a place to look. The symptoms you described were identical to mine, but they are gone now. FINALLY!

Sorry for the delayed response - computer crashed. Glad your problem is finally fixed. After using the SeaFoam, mine ran perfect for approx. 3.5 weeks. Now the hesitation will happen maybe once every 3 days. I notice it more now when I make a turn and accelerate. I'm wondering if I have water in my tank. I'm trying a fuel additive that removes water. If that doesn't work, I'm trying the MAF sensor. I have replaced the wires (no coils) and that did not help. Are coil packs expensive and did they say why they think the coil packs caused the problem?

Again, congrats on getting your problem fixed. We'll talk again when we have the next problem. Get ready for a starter. I'm replacing mine on Monday !!!!!! I'm glad I own a GS3 - 2 hour job-starter comes out the bottom. GS4- 6 hour job.

[jtamayo]

I bought SeaFoam at NAPA for approx. $ 7.50. You can also get it at most Pep Boys and Auto Zones. Add a full can to a full tank of fuel. Check out their website at www.seafoamsales.com. I drove 100 miles today and still no hesitation.

Looks like Seafoam fixed my hesitation problem. No hesitation in 1.5 weeks. Thanks to everyone that made suggestions and especially to Menappi for his Seafoam suggestion. He saved me a ton of money and aggravation. Thanks.

Have you had any hesitation since??? Lexus diagnosed mine with clogged catalytic converters; howver, that didn't fix the problem. So they replaced the wires and the coil packs. This solved the problem. So if you still have the problem this might be a place to look. The symptoms you described were identical to mine, but they are gone now. FINALLY!

Hello,

I too have been feeling this hesitation in my '02 GS430. I cleaned out my MAF the other day using CRC Mass Air Flow Sensor Cleaner but it didn't help. I'm going to try the Seafoam suggestion to see if that works and if not, I too will probably purchase wires and coil packs. Can you clarify that the wires I need to replace are the spark plug wires and the coil packs (ignition coil?) are what the spark plug wires are attached to? If that does not work, I'll look into replacing the MAF sensor. Where can I buy the wires and coils and MAF sensor for cheap? Thanks again everyone!

[scottie]

Cleaning the throttle body fixed my problem.

[sfm4103]

I bought SeaFoam at NAPA for approx. $ 7.50. You can also get it at most Pep Boys and Auto Zones. Add a full can to a full tank of fuel. Check out their website at www.seafoamsales.com. I drove 100 miles today and still no hesitation.

Looks like Seafoam fixed my hesitation problem. No hesitation in 1.5 weeks. Thanks to everyone that made suggestions and especially to Menappi for his Seafoam suggestion. He saved me a ton of money and aggravation. Thanks.

Have you had any hesitation since??? Lexus diagnosed mine with clogged catalytic converters; howver, that didn't fix the problem. So they replaced the wires and the coil packs. This solved the problem. So if you still have the problem this might be a place to look. The symptoms you described were identical to mine, but they are gone now. FINALLY!

Hello,

I too have been feeling this hesitation in my '02 GS430. I cleaned out my MAF the other day using CRC Mass Air Flow Sensor Cleaner but it didn't help. I'm going to try the Seafoam suggestion to see if that works and if not, I too will probably purchase wires and coil packs. Can you clarify that the wires I need to replace are the spark plug wires and the coil packs (ignition coil?) are what the spark plug wires are attached to? If that does not work, I'll look into replacing the MAF sensor. Where can I buy the wires and coils and MAF sensor for cheap? Thanks again everyone!

I finally fixed my problem by replacing the MAF sensor - $ 165 from Hoy Fox Toyota Lexus in Texas. They have great prices on Lexus factory parts. The link is http://www.trademotion.com/partlocator/ind...956&make=20

For some reason the Seafoam would mask the problem for several weeks, but it would gradually come back. The new MAF did the trick and it has been over 2 months without any hesitation.

[R.Holmes]

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

Same symtoms as my 98 ES300. Change the EGR Vacuum Modulator. Cleaning does no good. This solved my problem