mayad79

205,000 miles
1998 GS 400
One owner

Symptoms:

Car began hesitating after a short hwy drive. The problem is this is objective, but hitting gas feels smooth, getting to a light, shuddering begins. The warmer the car gets the worse it can be noticed. Kind of jerky.
Threw a check engine and VSC lights as I began to ditch safely as I felt it was off.

Signs:

After a tow to my mechanic I was told that the codes for all 8 cylinders showed misfire, and the VVTI.

I would include possible related events or personal opinions, but I think this way will be more subjective. I am currently searching our fine recources and have come up with much info.

Thanks to alls

mayad79

Some other signs that I noticed was that when the car is cold it starts, but as I let it warm, it acts up. Vibrating scarily as soon as it engages drive or reverse as the rpm drop down

What I'm thing is the timing belt is giving me a signal, when one shouldn't ever expect to get.

The VVTi component on the engine is maybe bad.

or, A batch of bad gas.

Any help would be appreciated. I won't critisize, even if you tell me to check my tire pressure.

Thanks yall

jcat_350

well if it's at 205k you should have had a 2nd timing belt done by now (usually 160 or 180 is recommended). this seems to be the problem as related to your VVTi and missing issues.

also, if the car is doing this when it heats up and vibrating upon gear selection, have the tranny flushed and get some new fluid in there. A decently easy DIY if you have the right stuff. Check the tranny pan for any sludge and clean it out.

if those still dont fix the missing, clean MAF, clean Throttle Body, check plugs, check coils, check injector voltage if all of that doesn't fix it, you should take it to the shop because it's probably pretty serious.

mayad79

I'm going to try is-heet tonight, just in case some bad gas.

LexFather

Sounds like the air/fuel sensor is gone. About a $150 part I think and around a $400+ job at the dealer.

mayad79

The iso heet did great!

I am still burning the fuel and still have the check engine light, but no more shaking.

Have been trying different scenarios, no problems today


thanks everyone

mayad79

Well I spoke too soon, at low rpm the shaking is back.

Car is going to be picked up, and be taken to the mechanic. I hear good things but have never serviced there. I don't want to give him too much info, until he has a chance to tell me what he thinks.

At the same time with 205,000 miles I will procede with:

1. timing belt
2. water pump
3. serpentine belt


Are there any other consumables that should be done?

peace,

mayad79

Well I heard from the mechanic today that the problem is certainly an electrical, computer problem. The 4 cylinders on the drivers side are fine but not firing correctly. He is narrowing down which sensor it is, and has mentioned, as one of our colleagues here did, that air /fuel is one of them.


I will keep updating


Thanks to all

JoelGs

iTrader: (1)

+1 on this one..I believe jcat_GS3 knows what he's talking about....

mayad79

Well the mechanic just checked the timing belt, and says that it is fine. I will change it out anyway, once I get an estimate on the electrical/computer cause.

It seems the 1sicklex's suggestion is closer to the real problem. The air/fuel sensor.

Does the VVT-I have sensor or selenoid that is part of standard maintenance?


Thanks for everyones help

mayad79

Well folks,
The idle control seems to be the problem. The ECU is fine, but the sensors are not. The problem has yet to be confiremed, but thanks for all the help.


Peace;....

Och

iTrader: (3)

What's an air/fuel sensor, I never heard of such.

mayad79

So,

The news is that the idle control has been replaced, the timing belt, serpentine belt, water pump.

The car is not misfiring in 4 cylinders and the ECU is fine (miscommunication), but there is a problem in one cylinder. The last issue with the cylinder is being diagnosed, but I am thinking that it may be as simple as a coil pack. I will keep this updated.....

If one coil pack is bad, should I change the rest out or anything else.


Thanks folks for all the help and the resources that are available.

JoelGs

iTrader: (1)

Also check on the ignition coils to see if that had been replace. If the car is misfired most likely the ignition coils went out. That what I would do first..

speedaddic

iTrader: (10)

you don't need to replace all 8...just the one if its bad...sounds like a misfire. Spark issues wouldve been the first thing I checked (ie: plugs, wires, coils)