# 99 VW New Beetle GLS 2.0 AEG Mysterious Throttle Surge/Limp Mode



## jbyrd117 (Jul 22, 2017)

Maybe someone on here knows what the heck is going on with my '99 2.0 AEG VW New Beetle GLS. My car keeps going into some sort of limp mode with a throttle surge at low RPMs after driving for a while. My european import auto shop is out of ideas since it's so inconsistent.

The first time this happened, I drove ~8 miles on the highway to get to work and when I got to work after stopping my car at a stop sign, it went into some sort of limp mode and would not accelerate past 10mph (while foot is on the pedal the car has a rhythmic throttle surge). Turning the car off and back on sometimes fixes the issue and lets me drive for another half mile/mile/several miles (it's random). So far it has only happened at low RPM's when my car has to slow down or be in start and stop conditions. Usually happens after driving for a while.

It has also thrown a P1543 (throttle actuation potentiometer signal too low) code and my throttle body was adjusted and replaced. Replacing the throttle body didn't fix the actual problem and the vagcom shows 5 different codes. My shop is out of ideas after checking voltages and things. Attached is the results from the Ross-Tech vagcom scan. I'm not ready to give up on this Beetle. HELP!


Cross posting this from the 2.0 liter engine forum.


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## ga22012jjeg (Oct 31, 2016)

So the car drives for a while then, it doesn't want to accelerate. Its intermittent. Question: is it just low on gas after a good long drive?

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## jbyrd117 (Jul 22, 2017)

ga22012jjeg said:


> So the car drives for a while then, it doesn't want to accelerate. Its intermittent. Question: is it just low on gas after a good long drive?
> 
> Sent from my SM-N950U using Tapatalk


Gas tank is almost full


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## ga22012jjeg (Oct 31, 2016)

No matter how fancy engines get, it's still simply true that for optimal performance the engine needs optimal air, water, fuel, and spark. Given the car's age I would suspect fuel delivery is compromised and its starved under high demand (acceleration after a stop) and not when demand is lean (at cruising speeds). I'd investigate fuel injection lines after I investigated the most likely culprit, the fuel pump.

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## jbyrd117 (Jul 22, 2017)

ga22012jjeg said:


> No matter how fancy engines get, it's still simply true that for optimal performance the engine needs optimal air, water, fuel, and spark. Given the car's age I would suspect fuel delivery is compromised and its starved under high demand (acceleration after a stop) and not when demand is lean (at cruising speeds). I'd investigate fuel injection lines after I investigated the most likely culprit, the fuel pump.
> 
> Sent from my SM-N950U using Tapatalk



Thanks I will look into that. I haven't had fuel pump issues except with the relay so maybe I'm due for fuel pump problems.


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## ga22012jjeg (Oct 31, 2016)

Let me know how it goes.

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## jbyrd117 (Jul 22, 2017)

ga22012jjeg said:


> Let me know how it goes.
> 
> Sent from my SM-N950U using Tapatalk



Will do!


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## robinson1509 (Nov 25, 2009)

Those codes are saying the ecu cannot compensate for the actual problem. Ignore the codes and look for the problem. I have seen those with a bad maff not saying that is the problem but if it is happening at low idle could be. Use the vag and log the live data when you have the problem. Fuel trims, battery voltage... it's not rocket science . Don't give up on it you just have to be smarter than the machine or at least the german engineers that design them.


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## jbyrd117 (Jul 22, 2017)

After cleaning the MAF sensor the issue has not happened again. Hopefully it stays this way.


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