I've had my Jetta about a year and a half now and it has 140,000 miles on it. In the past couple months it's developed several strange issues. I don't think any of them are really serious, but they are really annoying. I don't know much about cars, but I can usually do my own work as long as I know what's wrong.

Issue 1: It makes an annoying buzzing noise anytime the engine is running between 2600 and 2800 rpm, regardless of speed or gear. I can't quite tell whether it's a vibration buzzing noise or something rubbing on something, like maybe a fan. I'm thinking it's more likely that it is a vibration because of how it sounds, and the fact that it always happens at those engine speeds as if it is resonating. I'm not sure of the location either but it's definitely forward of the dash.

Issue 2: Right when I start it in the morning, if I don't let it warm up for a few minutes then when I start driving the oil signal starts going off. It did something similar before but it stopped when i replaced the low oil pressure sensor. I think it is the high oil pressure sensor this time, but I can't find it for some reason. The low sensor is obviously placed, but I can't see the other one. It might just be behind a hose or something.

Issue 3: Occasionally when I go over a bump the speedometer stops working, and the I'll go over another bump and it comes back on. Obviously a loose connection somewhere, but I don't don't know how best to locate it.


If anyone's had these problems please help, or if you have any tips on figuring out what's wrong that would be greatly appreciated too. Thanks.

 

As far as the noise goes, get under the hood and rev the trottle body and do some listening. I don't know too much about MKIII's but I'm pretty sure there is only one oil sensor, I've never heard of two sensors. It could just be going off because the oil is thick when it's cold in turn sending a low pressure reading to the ecu. What weight of oil do you use? I'd suggest 5W-40. I'd check your speed sensor connection on your transmission first but, beyond that you'll have to get a repair manual and follow the wiring diagrams.