Loss of Power - Potential Causes? Related to Injector replacements?

[nb99]

Hi

I'll start by saying and apologising that I'm not very good on cars so please go easy on me, but any thoughts/ideas would be much appreciated.

Quick history - A6 Avant late 2005. Just reached 100k miles. Until recently never had any serious issues. At the start of the year for the dreaded white smoke which was indeed the injectors. Had all 6 of those replaced as well as the fuel and oil filters back in early May - running perfectly since then....until yesterday.

The Problem - Wife driving the car (so details are a little sketchy) but steady driving at around 60mph, decelerating gently, she experienced light shuddering. In continued "light" driving in the next 5 mins the shuddering got worse until she stopped at a roundabout and couldn't move off from it at all. She thinks it did rev a little but not much when she tried to accelerate. She turned car off and tried to start again but car wouldn't start - she thinks it didn't turn over at all. 2 guys pushed her car off the road. 5 mins later she tried to start it and it started fine - she managed to drive home with no problems.

I tested the car yesterday evening for about 20mins including some hard acceleration - no problems at all. This morning I turned on engine and orange engine warning light is now on.

When I look up loss of power on the forums there seems to be loads of possible causes. Wondering if anyone had any thoughts. Is is likely/unlikely to linked to the change of injectors in May? If not what are possible causes? I'm bring it down to the garage shortly but just love if anyone had any pointers to discuss with them when I go.

Thanks v much.

[Amo Zirins]

It could be anything. Do full VCDS scan first


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[nb99]

Yeah I assume that's where the garage will start (it's an independent garage, not an Audi one just to clarify). Just wondered if there anything "obvious" it might be.

[nb99]

OK so the diagnostiques came back with 3 things which included the EGR valve, the Throttle body and something else (something about a column?) - sorry it's a bit vague but I live in France and was translating from French reading over the guy's shoulder. He seemed to think none of those would explain the symptoms so wiped all 3, told me to test it and come back if the motor warning light comes back on. However, now that I've read a bit about it, it seems to me like a dirty throttle body would explain it. I'd be happy to do it myself but seems I need some software to reprogram after so I can't?

Does any of that sound right to anyone?

[Amo Zirins]

Audi A6 C6: How to Clean and Reset Throttle Body | Audiworld


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[nb99]

Yeah saw that thanks and was all set to do it until step 5 which is throttle body alignment which needs software product and scanner tool. Pity.

[nb99]

OK - in case anyone else with the same problem. Engine warning light came back on and only error was the Throttle box. The garage is opening it up now to see if it needs a clean or full replacement.

[spottedhaggis]

I had something similar, driving with the engine revs at 1800 or more was fine, but I hit bad traffic on the M4 and when I started to drop below the 1800 revs the engine suddenly lost power, on off on off, rev neele going right down then up to 1k and so on, and it would after a few seconds of this stall. Id be able to get it started again but it would stall within a second, so the only way I was able to get where I was going was to wait for a big enough gap between me and the cars in front, start it and floor it, lol, I kept my hazards on the hole time, and when I was moving real slow I put it in N and coasted reving the engine. Got where I was going, and had my 1 hr meet, then when I got back and started it was fine, but then a little bit later on the M25 It reared its head again.

My issue was the EGR valve was 100% blocked up (132k) and replacing the EGR was going to cost more than having it blacked off and an ecu remap to wipe it out so if I were you I would do that

[nb99]

Sorry - should have updated this for future reference. Throttle body changed. Running perfectly ever since.