I'm back with another peculiar problem. Some of the problems ive seen in this car...Mind boggling!

Alright see if any one can make sense of this

After driving long distances my car seems to suddenly go into a fit and starts gasping. The RMP drops the accelerator for that moment does not respond and just before the RPM drops to below 200 it suddenly springs back to life with a jerk and the RPM suddenly jumping to meet the depressed pedal only to repeat after a couple of seconds.

The best part

1) This only happens after i drive long distances
2) If i turn the car off and let it cool the problem goes away
3) if i drive really fast the gasping stops
4) sometimes when i take turns the car switches off
5) VAG reports no error codes
6) Offlate my temperature seems to rise while idleing (thinking it might be the termostat although i had it changed recently)

Ive just changed the
1) Air filter
2) All 8 injectors
3) breather hose

and all this RnD is costing me a fortune but is not getting me anywhere

My mechanic now says that it might be the o2 sensor... I just though id get a second opinion from you guys

HELP!!!!!
B.Varghese
1997 A8Q tiptronic
United Arab Emirates

 

I am just takeing a wild guess, but could it be fuel related ( pump or filter )?

 

Check your MAF for cleenliness (I kno I spelt that rong). I think I say something in one of the other Audi forums about teh MAF housing being dirty and causing hesitation and drifting rpm.

 

Hey I think your mechanic has part of the right idea.

Normal aging process will eventually cause the oxygen sensor to fail. However, the sensor may also fail prematurely if it becomes contaminated with lead from leaded gasoline, phosphorus from excessive oil consumption or silicone from internal coolant leaks or using silicone sprays or gasket sealers on the engine. Environmental factors such as road splash, salt, oil and dirt can also cause a sensor to fail, as can mechanical stress or mishandling.

A dead sensor will prevent the onboard computer from making the necessary air/fuel corrections, causing the air/fuel mixture to run rich in the "open loop" mode of operation, resulting in much higher fuel consumption and emissions.

An additional consequence of any oxygen sensor failure may be damage to the catalytic converter. A rich operating condition causes the converter to run hotter than normal. If the converter gets hot enough, the catalyst substrate inside may actually melt forming a partial or complete blockage. The result can be a drastic drop in highway performance or stalling because of a buildup of backpressure in the exhaust system.

It sounds to me like this is your culprite!

51Timber

 

You're a "ringer," aren't you?

 

Sounds like a plugged fuel filter, failing fuel pump, or fuel pressure regulator, in that order.