I let my 99' Audi A4 1.8 sit for 3 weeks while I waited on parts. Now when i start it up and press on the gas it revs up for about 2 seconds and then falls back to idle. Even if I hold the gas pedal down constantly it will rev up for 2 seconds and then go back to idle over and over again. I'm lost. It didn't do this before I let it sit. Help????

 

scan it for codes and post up any. what parts were you replacing? auto or manual? quattro or FWD? have you checked for boost leaks yet? is the idle steady if you dont touch anything?

 

i would say vacum cause no fuel pump ur car wouldnt even start

 

Sorry I would typically give the codes first but I have to manually charge the battery due to a bad alternator. There were 2 codes.

17967.P1559 Throttle Valve Control Part-J338 Fault in basic

17953.P1545 Throttly Valve Control System Malfunction.

Anyone know if this is a DIY? I've replaced quite a bit on this Audi myself (not because I wanted to but because I live in DC and everyone rips you off here) and haven't had any problems so far. It's a manual FWD.

I just started it again today and now it revs up by itself without me pushing in on the gas pedal. It still falls to idle after about 2 seconds.

 

im not gonna say nothing really cause i dont know about the throttle valve control but that sounds electric to me so i would think you need a new one

 

I read something in a post about after having the battery disconnected (or in my case completely dead) that when you reconnect it the throttle control valve need to reset itself the first time you turn the ignition? I was stomping on the gas pedal the first time I turned it over as it had been almost a month since I last started it. I'm thinking this may have screwed with its calibration? Any thoughts? Maybe I should disconnect the battery again and try letting it reset.

 

you need vagcom to reset it i would say

 

I got the same exact problem... What you talk about by letting the car sit on ACC mode for 5 minutes is called "Throttle Body Adaptation" and you're supposed to hear some kind of little whine followed by a click out of the Throttle Body that indicates that the system has re-adjusted. I did it and heard the sound but my car still idles erratically...

Have you found a solution to your problem???

 

I haven't fixed it yet. I'm waiting on the Vag-com usb cable I ordered to get here so I can force the adaptation. If that doesn't work I'm going to assume that the TB is unable to adapt and that I need a new one. Pain in the ***. This all started with needing a new alternator. Classic B5 where one problem turns into 2-3.

 

By idle do you mean that the engine stops or revs at ~800?

I was locking my car once and my key split in two (no remote locking, a torch in the key, splits to change the battery). When i came back to my car it would rev for two seconds then stop. If i held down the gas it would rev faster for 2 seconds then stop. The problem was that the immobiliser chip fell out of my key, (looks like a small grain of rice). Thankfully after leaving the car where it was (a multistory carpark for 3 days i managed to find the immobiliser under the car. Put it back into the key and after a couple of tries it started right up. I understand you are getting fault readings, but they may be unrelated.