Need help determining whats wrong

Asked by Sep 26, 2017 at 02:52 PM about the 2003 Volkswagen Jetta GL 2.0

Question type: Maintenance & Repair

My car is a 03 Jetta got it about a year ago. I believe it was left mostly sitting
in one spot for long period(s) of time. The roof clear coat shipping off ever so
Managed to fix most of what was wrong with it. But now I'm experiencing
something weird with the engine. I know that the thing doesn't have to much
HP and/or torque. So I plan accordingly when it comes to gassing it. But
sometimes I have no choice. When I gas it too "hard" the engine kicks a bit.
and it blinks the check engine light. I know i have something wrong with a
vacuum tube. But I'm not sure if that's the cause of it.

13 Answers


Blinking check engine light is not good. It means you are in danger of ruining your catalytic converter. I would definitely fix your vacuum issue as this can cause your issue. A few dollars worth of vacuum line is not worth $1500.00 catalytic converter. You have too much unburned fuel getting to your converter.

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Best Answer Mark helpful

Oh dam. That doesn't sound too good. Also forgot to mention when the car is in idle, not moving just in park. The RPM needle keep jumping up and down. Not by a whole lot but its noticeable. And I'm not 100% about the vacuum itself. I just asked a friend and he said that what it was. Every time I try to actively try to find a replacement I can never find it. I eventually just pulled one off a '02-'04 Jetta in the junkyard. Once i get out of school i can take pictures of the tube I'm referring too.


All parts stores carry this vacuum line. Use hose clamps or constant pressure clamps. Take a picture if it has special ends or something of that nature. Do you have a check engine light constantly on? Read the code and start there. Some code readers can check for historical codes if the light is not on at the time of checking. Does sound vacuum related. Your computer is throwing extra gas in the engine to overcompensate for all the unmetered air

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Ok in this pic I'm showing the "hose" or "tube" that I had/have problems with. And yes, when i turn the car on it usually makes a noticeable "sucking" sound. The sound was significantly louder before I replaced it with another used one. And yea I'm gonna try to ask around to find a code reader. The engine light as of now is constantly on, sometimes in a really cold night/morning the check engine light doesn't come on. And then from there, it only comes back on when I gas it too hard.


This makes sense that a cold engine needs more gas. The light is not on when cold because it is already getting too much gas because of the issue and being cold it needs more gas. Code readers are really cheap on EBay. Get the MS300 from Autel. $10 - $13. Great reviews. I have 3 of them one in each car. For now autozone might be able to read code or pull a historical code for you?

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NAPA or any parts store would sell you that piece for like $4. Buy new clamps. Keep in mind that fixing one vacuum leak might uncover another because of the age of the rubber hoses. I buy 4 feet at a time of all different diameters for this reason.

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Yea definitely. Now, is this issue time sensitive? Because I've been driving with this issue for a while, and on 300 mile trip. Not recently but a while ago. Currently I'm waiting for the miles to come up to 3k. So I can do an oil change. Was wondering if I can hold off on it till then or fix the issue before then. Thanks so much for your help.


I am guessing you will get a code that says large vacuum leak. I would not drive this vehicle if it was mine. Ruining a catalytic converter is expensive and sometimes aftermarket parts do not fix the issue and OEM are crazy expensive. I would be outside replacing vacuum lines if it was my car. You also could have a gasket leaking on your intake that would show up with a smoke test. There is a video on YouTube on how to make a smoke machine for cars. You could do this and find your other leaks. How does the evap canister and the hoses going to it look?

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You also could have a bad gas cap. (Seal on it)

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****UPDATE**** Ok first off I would like to thank you a lot for your help, and also sorry for not responding after your last. About 3 days ago I went to O'Reillys to get my check engine light checked. Two codes came back; P0302 Cylinder 2 misfire and 532 Battery voltage to small. So after o got that information I did quite a bit of research. Deduced that code P0302 was coming from a bad spark plug wire or the spark plug itself. From my research I believed that code 532 was in relation to P0302. Therefore, I maintained my focus of P0302. I bought new spark plug wires and spark plugs. Just today I tried to do it and sort of succeeded, I was unable to remove spark plugs 1 and 4. I feared I would crack the manifold. But i managed to change spark plugs 2 and 3. I did however, change all 4 spark plug wires. I accidentally broke the vacuum tube that is on the left of the manifold, but managed to get a replacement for that. I also replaced the gas cap. The seal was riddled with tears. Overall, once said and done. The car is working just fine now. Tried to replicate the situations in which the issue would normally be caused, but alas! Issue gone. Oh by the way, I think i found the main culprit here. Just take a look at the picture...


Wow yeah I think that would do it. I once had a spark plug that the resistor was even with the ceramic. Good job on the fix try those other spark plugs when the car has been in about 3 minutes. Maybe even drop a small bit of oil down and work them back and forth.


Car has been on about 3 minutes

Yea honestly If i had the whole day I would of worked something out but I had work. I was crunching time at that point. Probably find another day to replace the other one. But yea, as of now no check engine light is on and the engine purrs nicely. Well ass nicely for a 13 year old car.

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