Hi all, I could use some help..

When it's cold, which is always, my car runs horribly. If I give it any gas it wants to stall. Sometimes it acts like it's going to stall without me touching the pedal. It's embarassing and dangerous. When the engine warms up the car runs fine.

I replaced the vacuum line connected to the combination valve, which was completely busted. This didn't seem to help. This was the only vacuum line I checked. The vacuum pressure is about -18 psi. Does this mean all my vacuum lines are good?

The boost gauge spikes to about 22 psi, but it could be more because the gauge maxes out at 20. The boost then falls to about 15 psi quickly.

Recently I have had the code P0411, secondary air flow inadequate. I don't know if replacing the line coming from the combi. valve has fixed this or not. Will the CEL shut off on it's own?

I have a manual tranny.

I did check similar threads but wasn't able to find a solution.

Thanks for any advice anyone has!

edited for grammar.

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2000 A4 1.8t
k04, GIAC tuned, H&R springs + Bilstein struts, DV, AFPR, K&N air filter, Boost and Air/Fuel gauges
17" wheels, rs4 grill, 18% reflective tint

Have the codes read then clear them and see what comes back. Codes will be stored until cleared.

My guess, assuming that your spark plugs are OK and that there are no more vacuum leaks is the temperature sending unit. However, that is a guess from half the world away.

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2000 A4 1.8T Quattro tip
APR 93 chip
710N
ECS N75 Race Valve
Tip Chip
Borla Exhaust
Sports Suspension
Cracked windshield (again), 3rd timing belt

I went and had the codes read today. The only one that showed up was the P0411 Secondary air flow inadequate, which may or may not be fixed. I've cleared the codes and will see if they reappear. This couldn't cause my problems with the cold though could it?

The guy at auto zone said it might be the plugs too. Should I just go ahead and replace them?

Any other ideas?

Thanks

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2000 A4 1.8t
k04, GIAC tuned, H&R springs + Bilstein struts, DV, AFPR, K&N air filter, Boost and Air/Fuel gauges
17" wheels, rs4 grill, 18% reflective tint

Frankly I doubt it is plugs. How many miles on the car?

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2000 A4 1.8T Quattro tip
APR 93 chip
710N
ECS N75 Race Valve
Tip Chip
Borla Exhaust
Sports Suspension
Cracked windshield (again), 3rd timing belt

There's 68,000 miles on it. I was really hoping it would be something easy like plugs!

Thanks for your help!

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2000 A4 1.8t
k04, GIAC tuned, H&R springs + Bilstein struts, DV, AFPR, K&N air filter, Boost and Air/Fuel gauges
17" wheels, rs4 grill, 18% reflective tint

oh, I should probably mention this..

Yesterday when driving at about 60, not accelerating and not boosting very hard, my EPC light came on and the car shut off while driving. I restarted it and everything seemed fine. This has happened a couple of times. Perhaps this has something to do with it?

There is currently no CEL.

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2000 A4 1.8t
k04, GIAC tuned, H&R springs + Bilstein struts, DV, AFPR, K&N air filter, Boost and Air/Fuel gauges
17" wheels, rs4 grill, 18% reflective tint

If it only does it while cold, it could very well be the failed secondary air pump.

It only runs while the car is cold.

Its located under the airbox, there could be a leak in the hoses to it, or it could need a good cleaning, or may need replaced.

try a search for "secondary air pump", I bet you'll find a few that had similar issues as yours. Its worth a look at anyway.

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Acetrebo
"because life is too short to drive bad cars"

Really? Someone told me that it was just an emissions device - burns unburnt fuel particles in the exhaust when starting, and had no effect on the car's performance.

I'll have to further inspect it tomorrow. Thank you

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2000 A4 1.8t
k04, GIAC tuned, H&R springs + Bilstein struts, DV, AFPR, K&N air filter, Boost and Air/Fuel gauges
17" wheels, rs4 grill, 18% reflective tint