Loss of power

[DarCar]

Not sure if anyone can help me but I thought I would give it a shot as my mechanic is at a lose as well.


Problem is sometimes at startup (now almost 100% of the time) the engine feels like it is shaking almost like it is about to stall but if I rev the engine for about 1 minute the problem goes away and I can drive normally until the 23minute mark (problem almost always happens at the 23min mark) the same problem occurs. The engine feels like it is shaking, I have a loss of power and when pushing on the gas it feels like your riding a bike and the chain is skipping a tooth on the gear while at low rpms. The engine light flashs during this time. Sometimes the car returns to normal without restarting the engine and sometimes it doesn't.

My repair guy has changed all the Spark plugs and coils as well as the fuel pump. My battery is about 4 months old.

any help would be great thank you

[old guy]

It sounds like you are working with a mechanic who doesn't have VAG specific diagnostic capabilities. Can the mechanic hook up to your OBD2 port and pull the DTC's (diagnostic test codes) specific to your car? Once you get the codes it will be much easier to diagnose your problem. It sounds like a failing coil pack (although you stated that you already replaced the coils and plugs). Also can you give a little more information on your car? Is it a 1.8T? 3.0? How many miles? What year?

[DarCar]

Sorry A4 1.8T 2002 i'll see if i can get the error code from him. 120,000Km so like 75,000 miles


these are the error codes

1st p1293 f265
2nd p1602 - j271
3rd p0118
4th p0300
5th p0304
6th p0303
7th p0685

[old guy]

Sorry A4 1.8T 2002 i'll see if i can get the error code from him. 120,000Km so like 75,000 miles


these are the error codes

1st p1293 f265
2nd p1602 - j271
3rd p0118
4th p0300
5th p0304
6th p0303
7th p0685

Code P1293 indicates a problem with your MAP controlled thermostat.
Code P1602 is a low voltage code. That one probably came from when you replaced your battery.
Code P0118 indicates a problem with your G62 temperature sensor. Clicky click (http://wiki.ross-tech.com/index.php/16502/P0118/000280)
Code P0300 is a random misfire code.
Code P0303 and 304 are specific misfires on cylinder 3 and 4.
Code P0685 indicates that the ECM power relay control is open. This also probably came from when you replaced your battery.

I would start with replacing the G62 coolant temperature sensor. Clicky click. (http://www.audiworld.com/tech/eng66.shtml) The ECU makes fueling adjustments based on the engine temperature. If the signal is out of whack your fueling will be off and can cause performance issues (misfires, power loss, etc). You should also check out the MAP controlled thermostat, but I would start with the G62 first because it is a lot cheaper and easier to replace.

Good luck!

[rbretch]

Coolant temp is more than likely the problem. But you need to clear the codes out and start fresh. The ecu will correct itself for diffrent codes and you could be going after a ghost code. Clear and see what codes come back. The 685 code can be from more than just a battery change.