Four problems related to manifold/header/muffler/tail pipe have been reported for the 1999 Volkswagen Jetta. The most recently reported issues are listed below.
Manifold and oil cooler plug with carbon. Dealer indicates that Volkswagen, knows about the problem, and has yet to offer any remedies. This problem leads to a very costly cleaning.
Loss of power while accelerating. Vehicle taken to dealer shop and informed that problem was due to a faulty mass air flow sensor. Feel free to provide any further information.
Engine checklight came on with engine running rough. Dealer diagnosed broken mass air flow sensor and replaced. Manufacturer refused to extend warranty to this part. Many other owners report this part failing at 20k to 40k miles.
The mass air flow sensor went out after they replaced the oxygen sensor and they want $550. 00 to replace the sensor which I believe is their problem this is an ongoing problem with the 1999 Jetta, and I feel they should replace it at no cost a car that is not even 3 years old should not need a new mass air flow sensor. I am very unhappy with vw and I will never buy another or recommend them to anyone.