# Sudden loss of power/acceleration ... any idea?



## Euro_Touge_Driver (Oct 11, 2006)

While driving home from my girlfriend's house (raining outside), my GLI suddenly lost acceleration on 6th gear (a good second) while my foot is on the gas, then it accelerated again. I was on the freeway traveling at 70 mph when this happened. I freaked out a bit since there was a bit of traffic around me. So I took the nearest exit and shifted back to neutral, stopping at a stop sign, then I shifted back to first gear with the clutch engaged. While letting go the clutch normally, the car suddenly had a hard/violent jerk and a bit of hesitation, then it drove normally again. No CEL or any other warning light on the dash. This is getting me a bit concerned since I recently got it serviced. Could it be a battery problem since VW noted that my battery isn't able to hold a charge or could it be something else mechanical or electrical?

**Note: I'm a bit new to the VR6 24v engine, so I don't know too much about it.

Some facts:
-100k mile service from VW was recently done.
-VW noted that I need a new battery
-Also noted that I need to replace my CV boot.
-No other problems pointed out other than the two noted above.

-Got clutch, master cylinder, and throw-out bearing replaced about 25k miles ago.


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## jlsgli89-03 (Aug 25, 2003)

did the power comeback? might be either of two things coil pack or MAF sensor. by the way did you get gas before this happened. maybe just some bad gas? either way there might be a code stored now in the ECU .go to an auto store and get a scan done.


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## Euro_Touge_Driver (Oct 11, 2006)

The power came back after it happened. This also happened 2 weeks ago while driving on the highway, but it was barely unnoticeable. I did get some fuel before driving (about 2 gallons). Used Chevron gas. Been using that gas for a long time and it improved my mpg compared to Shell for some reason. Right now, the gas is nearly empty so I have to refuel soon. I'm already speculating that the MAF might be the culprit (it might need some cleaning). The coil pack seems to be in good shape since my buddy replaced one of them before during my 80k mile service. Despite the CEL not showing up on the dash, I'll get my local auto store to scan for codes. I'll post them up here if any.


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## jlsgli89-03 (Aug 25, 2003)

good idea. trust me I had a coil pack just crap out on me and it looked in good shape. Its the nature of these things.


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## Euro_Touge_Driver (Oct 11, 2006)

Okay, so here's some news. Autozone cannot perform any OBD tests 'cause some law has passed here in the state of CA. Pepboys doesn't have a specific adapter to run the test. With those scratched out, I visited a local shop and asked them to run the test. Turned out it passed and there where no codes present. I told them the same exact story of what happened last night and they said that it could probably be the battery that's causing the problem. I mentioned about the coil pack and MAF to them and they said that if that's the problem, then the CEL should remain on and the codes being present.

So I guess I have to replace the battery to eliminate this issue.

Aside from the battery thing, are there any ideas that might cause the problem?

Note: I just put fuel injector cleaner, drove around for awhile, then refueled after. I notice a bit of hesitation while on 1st and 2nd gear then it drove normally after.

Another fact that I left out was my O2M transmission being rebuilt nearly 20k miles ago (long story short, the shift fork broke on me) since Pepboys said that it might be a transmission issue due to the violent jerk when I was on first gear.


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## jlsgli89-03 (Aug 25, 2003)

yes the CEL should remain in stored codes so that counts that out. I'd test the battery and maybe look into a fuel problem. clogged filter or maybe even a failing pump. if it jerks and bucks that's usually a sign of ignition issues and not fuel if I'm correct. Well use that rule of thumb. Go with the least expensive thing first. like maybe a new fuel filter.


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## Euro_Touge_Driver (Oct 11, 2006)

I will. The fuel filter was replaced when my buddy performed the 80k mile service, but I'll look into that. I just tested the battery from Autozone and they said its really bad. Its not able to hold a charge. I guess I'll get a new one to see if it solves the ignition/sudden loss of power issue. If not, then I'll probably buy a new set of coil packs. As for the fuel pump, I'm not sure, but I'll look into that as well.

In a few weeks, I'll let VW perform a throttle body service since its never been cleaned or touched. Not sure if it will improve it, but its worth a try.

I'll update on here if something happens or if there's any improvement.


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## jlsgli89-03 (Aug 25, 2003)

that's most likely your issue. the electrical systems re very touchy. They need that proper voltage or crazy things happen.


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## Euro_Touge_Driver (Oct 11, 2006)

Here's an update....On Monday, I installed the new battery and autozone tested the alternator and other ignition modules. They all pass the test and they're in working order. Now, while driving back home, I've notice a slight hesitation on all gears while accelerating. It just seemed like the car is having a hard time to pick up speed/RPMs during acceleration. So now, I assumed that its the throttle body or just a dirty MAF. I phoned in VW regarding about the issue and they'll perform a throttle body service along with cleaning out the MAF this coming Monday. If that doesn't work then its most likely the fuel pump failing on me. 

I'll update again after VW solves the issue.


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## jlsgli89-03 (Aug 25, 2003)

Been thinking about getting my fuel Injectors serviced too. Got 80,000 cars 10 years old now. might not hurt.


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## Euro_Touge_Driver (Oct 11, 2006)

I see. Well, VW diagnose the whole thing and it turns out I have a bad fuel pump. I'm going to replace the unit along with the fuel filter. 

I'm just wondering, I have a bad micro switch in the door latch (its been like that for a year) and it doesn't do that fuel pump prime as well as the interior lights not turning on when the driver-side door opens. Will that effect the new fuel pump on not putting fuel into to the engine? Or do I have to replace the door latch in order for the fuel pump to be functional?


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## rfoster1120 (May 25, 2012)

Sounds like a crankshaft positioning sensor or otherwise known as impulse sensor. It reads the engine speed and RPM. When it starts to fail it feels like the car is jerking or hesitating. I will become intermittent and get worse with time. Its a simple fix. For the 24V the part number is 022957147. ECS has it for a decent priced there part # is es4639. This sounds like what I just went through.


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## turbo4motion (Jun 12, 2007)

Euro_Touge_Driver said:


> I'm just wondering, I have a bad micro switch in the door latch (its been like that for a year) and it doesn't do that fuel pump prime as well as the interior lights not turning on when the driver-side door opens. Will that effect the new fuel pump on not putting fuel into to the engine? Or do I have to replace the door latch in order for the fuel pump to be functional?


 Door switch shouldn't matter. When you turn the key on the pump should prime again anyway. Mine has been like that for years. 
Only issue I have is that when I haven't driven the car for a few weeks, some fuel in the lines must evaporate, and the pump doesn't run long enough from the key to prime the fuel system. I just turn the ignition on/off a few times and it's sweet. 
Also, the door latch usually doesn't need to be replaced. You just resolder some of the solder joints on the latch module. But it's a pita to get at, which is why I've delayed fixing mine.


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## Euro_Touge_Driver (Oct 11, 2006)

Here's an update: Good news, power is restored and its running the way it use to be before this all happened. It was actually the fuel pump causing the loss of power. I bought both the fuel pump and filter and let VW do the installation. With the throttle body service done by them, the car is running more smoothly than before. 



rfoster1120 said:


> Sounds like a crankshaft positioning sensor or otherwise known as impulse sensor. It reads the engine speed and RPM. When it starts to fail it feels like the car is jerking or hesitating. I will become intermittent and get worse with time. Its a simple fix. For the 24V the part number is 022957147. ECS has it for a decent priced there part # is es4639. This sounds like what I just went through.


Will that show up as a CEL or some code read on the scanner? If its the crankshaft position sensor, should I be misfiring at one point? 'cause none of that happened, but I'll put that into consideration and keep that part # in mind. Thanks for your input.



turbo4motion said:


> Door switch shouldn't matter. When you turn the key on the pump should prime again anyway. Mine has been like that for years.
> Only issue I have is that when I haven't driven the car for a few weeks, some fuel in the lines must evaporate, and the pump doesn't run long enough from the key to prime the fuel system. I just turn the ignition on/off a few times and it's sweet.
> Also, the door latch usually doesn't need to be replaced. You just resolder some of the solder joints on the latch module. But it's a pita to get at, which is why I've delayed fixing mine.


Oh okay. I guess its just a minor issue. Right now, I don't have the money to buy a new module or the skills to resolder the joints. So I'll just leave it alone for now until the unit becomes fully disabled. Thanks for your input.


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## LosDub (Aug 18, 2008)

check your rear crankshaft seal


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