Again engine problems? WTH???

Hi,

today I was with my family on shopping tour, and drove on the highway 10 kilometers, and where we drove on exit the Lumina was shaking, the whole car.

The RPM was stable @1000 and the Lumina drive normal, but just on stand the car was shaking.

I muffler mades some noise I recorded it:

YouTube (http://www.youtube.com/watch?v=dVThWd6OLhA)

I checked the fluids and all was fine, ok once all 2-3 month I must fill some water not lot just 0,2 Liters.

The oil looks normally. I didnt find any failure, before three weeks the car had the same problem. After restart the engine all is fine.

Im desperate so please help me.... The same symptoms was last year the same, and it was gone for a year now its back...

I have new plugs, new wires, new air filter, new coils and new fluids and nothing changed.

Oh here is a Picture from oil fill in hole, but my gf drive everyday just short ways, so I didnt think its from leaking head gasket:

http://img301.imageshack.us/img301/8265/oiedsc0044413272.th.jpg (http://img301.imageshack.us/i/oiedsc0044413272.jpg/)

It appears that there is some water present, but it may be only atmospheric water (kondensat). The short drives every day may not allow the engine to reach full temperature long enough to keep moisture out. Periodically driving the car on a longer trip is good. Since you are adding only 0,2L every 2-3 months a large leak is not likely. You should verify the PCV system is working properly (kurbelgehäuse ventilation ist arbeitend).

Are there any unusual mechanical noises from the engine? The sound of the exhaust indicates a serious misfire or fuel mixture problem. That could be an ignition problem or fuel injector problem.

http://www.wwdsltd.com/files/McLin3,1LV-6OelFil.jpg

Is this the 3,8L Buick engine or the 3,1L Chevrolet engine? The Chevrolet engine can suffer valve train damage from moisture in the oil more readily than the Buick engine. The Buick engine is more likely to have ignition control problems. Both can suffer injector problems.

Are there any error codes? Is the "Check Engine" lamp on?

I replaced the PCV Valve last year in summer. Same with ignition coil and module.

I have an OBD scanner (ScanXL with GM extension) and there are no errors and if the symptoms come the service lamp does not light.

The Lumina has the 3.8L V6 Engine Series II.

If the injector failure then the Lumina gives an trouble code, right?

Last time the engine made trouble the engine wont turn on, then I wait 20 seconds and then the engine runs fine. Now the engine run like the symptoms was never there.

Hope the information are what u need.

Low fuel pressure and sticking or poorly atomizing injectors will not set any error codes until they have degraded to the point where there is detectable misfire. Even then, the error codes will be generic and not necessarily indicative of the actual problem to the degree that we would normally expect.

Again the same problem, my gf said the brake pedal was very hard to press, maybe anybody another idea?

both could be caused by a vacuum leak

Check diaphram in brake booster & valve @ brake booster housing. Not necesarily in that order. Follow vac. line from booster to point of origin.