Car won't go
#1
02-13-2009, 07:44 PM
Car won't go
I have recently bought a 2001 a6 2.7t auto. When I got the car, it ran silky smooth but was low on power (0-60 in about 11 seconds). Last weekend I replaced the Mass Air Flow Sensor. After driving it for a week I start to notice a bit more power.
However today, as I pulled away from the stoplight the car starts to act up. The RPMs bounce from about 1-3 and the car just doesn't go. The dashboard lights up with ABS, Check Engine, and the other one for stability control (ECS?). I pull over and pop the hood to see if I can't see anything obvious. While the motor is attempting to idle, I hear a couple of "bppt" sounds. The sound is the motor blowing air OUT of the airbox in a quick burst randomly at about 10 second intervals. So I shut the car off.
I restart the car to see what it does. It idles perfectly. So I give it some gas. Nothing. Pump the gas pedal. Nothing. Still idling. So I turn it off, unplug the battery and wait. Plug the battery back in and start the car. Check engine light went out but ABS and stability control lights are still on. The motor still idles fine but does not react to the gas pedal. If I put it in drive it will slowly creep forward like normal but does not react to the gas pedal.
I did notice my spyder valve broke off a while ago. I temporarily latched it back on until I get a new one (at the dealer). It was still attached when I checked it.
I am guessing the problem is either a bad MAF sensor that I put in, a vacuum leak around the spyder valve, or maybe a throttle position sensor. Let me know what you guys think. Any input is helpful! Thanks.
However today, as I pulled away from the stoplight the car starts to act up. The RPMs bounce from about 1-3 and the car just doesn't go. The dashboard lights up with ABS, Check Engine, and the other one for stability control (ECS?). I pull over and pop the hood to see if I can't see anything obvious. While the motor is attempting to idle, I hear a couple of "bppt" sounds. The sound is the motor blowing air OUT of the airbox in a quick burst randomly at about 10 second intervals. So I shut the car off.
I restart the car to see what it does. It idles perfectly. So I give it some gas. Nothing. Pump the gas pedal. Nothing. Still idling. So I turn it off, unplug the battery and wait. Plug the battery back in and start the car. Check engine light went out but ABS and stability control lights are still on. The motor still idles fine but does not react to the gas pedal. If I put it in drive it will slowly creep forward like normal but does not react to the gas pedal.
I did notice my spyder valve broke off a while ago. I temporarily latched it back on until I get a new one (at the dealer). It was still attached when I checked it.
I am guessing the problem is either a bad MAF sensor that I put in, a vacuum leak around the spyder valve, or maybe a throttle position sensor. Let me know what you guys think. Any input is helpful! Thanks.
#2
02-14-2009, 07:27 AM
Your problem is bigger than the items mentioned. The car would not idle smoothly if you have a vaccum leak. A bad TPS will cause a CEL but the car will still respond as the throttle will still be opening up. A bad MAF would cause a CEL but the car would still go. Is your throttle cable still functioning? Sounds like it is broken.
Good luck,
Bob
Good luck,
Bob
#3
02-22-2009, 11:12 AM
I got the car back from the shop today. It turns out it was the throttle body assembly which had gone bad. The car is drive by wire with no throttle cable.