Spartan

I have a 2000 GS400 that is not driven during the winter months. It is definately babied but driven hard. I took it out of winter storage this last weekend and was tooling around town when I noticed that the car had a hesitation when applying the gas. Almost like a sputter. The check engine light eventually came on. The car has a Borla exhaust and an SRT intake system on it. I am not the most technical person, but I noticed that it had a very rough idle where as before it was perfectly stable. I popped hood and instead of the normal intake noise of a constant sucking....I noticed that the intake was sort of sputtering. I noticed the same sort of sputter from the exhaust.

Any ideas before I make a trip to the dealer?

I would appreciate any help.

Thanks
MIKE

Debonair

Find someone like Autozone to pull that code for you for free before you pay the $100 dealer diag. If its a simple fix you will have saved some cash - if its not then you lost nothing.

Once you get that code post it up - there are lots of people on CL that can help you.

Edit:
Almost forgot to tell you to check your battery cable connections. you'd be surprised what problems a voltage drop to the computer can cause

Spartan

After pulling the fault code at Autozone, I have come to find out Cylinder #1 is misfiring for one reason or another. There was no code #, the reader just spit out Cylinder # misfire.

Any ideas? A bad spark plug?

How hard would it be to get to the spark plug for Cylinder #1 or do you have to replace them all in sets?

Dealer wants $225 - $250 to replace all of the plugs. Not even sure if this is the problem, but it sure sounds like it.

When accelerating the car has a nasty vibration. Check engine light is flashing, while VSC and VSC OFF are constantly ON. Can not toggle on and off.

Thanks in advance for the help.
MIKE

GSteg

iTrader: (15)

it's best to change all 8 plugs for optimal performance. OEM plugs are iridium so go with NGK or Denso. They're very DIY'able. Should take you less than an hour. You'll need one of those u-joints attachment for one of the spark plugs.

Also note that it could also be your coilpack for that particular cylinder.

Spartan

How can you tell if it is only the coil pack?

Do you need to take the resistance of the coil pack?

The GS400 manual is pretty tough to read....at least for me

Any idea if it is worth getting some Torquemaster plugs?

Thanks
MIKE

GSteg

iTrader: (15)

Easiest way to tell is to change the spark plugs to see if the misfire is still there or not. It's probably time to change them anyways. Or you can probably change the coil from one cylinder to another and get the car scanned again and see if the misfire follows it. It's probably best to switch the coil pack while you're at autozone rather than running around with it. Too bad autozone's scanner isn't that great. They aren't really specific in telling you the exact problem.

If you have a megger (which I doubt most people do), then you can check the resistance of the spark plugs. For our cars, the resistance should be at least 10 MΩ

Spartan

Yeah the DRB the guy used looked pretty generic. I was glad to get as much information as I did.

How bad is it to drive the car back and forth to places like Autozone with misfiring?

It is my second car so I do not have to use it so I most likely will not.

Any recommendations beyond the stock plugs as far as Torquemaster or Pulstar? I guess while I am at it I might as well upgrade if it is worth it

Thanks for the help.

MIKE

Debonair

A cylinder #1 misfire is usually a P0301, the last number changes with each cylinder (P0301-P0308). I agree with Gsteg about changing the coil from #1 cylinder to another and then checking if it sets another DTC for that cylinder.

You might want to invest in a hand held diagnostic scanner of your own so you don't have to drive your car down to Autozone.. Some are as cheap as $50.

98LexLs

since the vehicle has not been driven for awhile i would check to make sure no animal has chewed on your injector wire.

Spartan

I removed the coil pack from Cylinder #1. Simple job.
Took it to the dealer but they could not tell me if it was good or not without sticking it on a car. The megger he said was only for the coils themselves but there was no way he could test the ingniter. I am going to swap coil packs from Cylinders 1 and 3 and see if #3 pulls a fault code.

If it does then I will replace the coil pack at $103.15 per pack!!! Dealer prices are just outragous.

If the coilpacks work then I will replace all the spark plugs. IS there any quality difference between the stock Denso or NGK plugs?

I tried just a regular 5/8 plug socket and it would not grab the plug. Do I need the deep socket because of the length of the top end of the plug?

The technician also said he has seen plenty of injectors going bad because of bad gas lately. Who knows.

Thanks for the help thus far.

MIKE

GSteg

iTrader: (15)

A megger CAN be used to check the spark plug. How do I know? Because it specifically said so in the Lexus repair manual for the GS. Either the guy doesn't know what a megger is or he's trying to get you to buy parts.

You'll need a deep socket 5/8" that's made for spark plugs. It'll have a rubber boot inside to hold the plugs. Denso or NGK, they're both fine for the car. You wont notice a difference.

As for the coil pack, you can buy it for $80+shipping from carson toyota (l-tunedparts.com). It should still come out to be ~$20 cheaper even with shipping because you'll pay tax at your local dealer anyways.

Spartan

I asked if the megger could be used for the coil pack. He said it could but not for the igniter portion. He recommended leaving the existing spark plug in, getting a new one and hooking it up to the suspect coil pack and grounding it. Then starting the car. If the car starts then the coil pack is fine. I somehow think that is hoky. I did not ask him to test the spark plug.

I had a "spark plug" socket but it was not a deep one. I think I will pick one up at Sears if I need to indeed replace the plugs.

Thanks
MIKE

Spartan

Something like this should not take so long....

I swapped coilpacks from the BAD cylinder #1 and cylinder #4 (because it was easy to get to). The fault code repeated at cylinder #1. At this point I ordered some plugs. Tonight I will replace all the spark plugs. If this does not work then back to square one.

Thanks
MIKE

Lex Tech

Did you check the wiring harness for the #1 injector and plug to make sure it wasn't chewed like someone suggested earlier?

Spartan

Well over the weekend I decided to change out the spark plugs. Cylinder #1 was the problem. That plug looked like it had a lot of carbon deposits. As soon as I replaced #1 I started the GS and it fired right up and sounded great! Problem solved. I proceeded to change all the other plugs. I ran into another problem though. When you take the coil packs out they are pretty difficult to remove even if you twist them back and forth and pull hard. They really stuck onto the head of the spark plug. I pulled one coil pack out and the rubber boot stayed in the chamber still attached to the plugs head

I finally worked the boot loose from the spark plug. It was either suctioned on pretty good or partially melted onto the plug head. Just a warning to anyone attempting to do this job.

All is well now. Thanks for the help from everyone who had input

MIKE