Skip the auto shop - Our mechanics make house calls

Q: Rough idle and low power

asked by on

I have a 12v vr6 Jetta. The other day, driving to my job, no problems. When I left, the car is louder than normal, rumbly almost like a v8 and is very sluggish. My timing chain has been making noise so I took the valve cover off and set car to TDC. Cams look to be in line, as I was thinking it may have jumped a tooth. Doesn't seem to be the issue. Any other advice? No engine codes. Wires, plugs, coil pack all replaced recently.

My car has 187000 miles.
My car has a manual transmission.

Hi, thanks for writing in. It sounds like you have timing chain related problems for sure. The central component, your timing chain, which maintains a critical relationship between the crankshaft, and the camshafts on your engine, has likely chewed up the timing chain guides enough to alter the cam timing. The expanded list of possibilities includes: worn-out timing chain guides, failed timing chain tensioner, stretched timing chain, or, as you mention, one of the timing sprockets has jumped a tooth. All of these components wear with extended mileage such as your vehicle has, and must be serviced. When they are severely worn, cam timing can vary enough to cause a "valve-to-piston collision", leading in most cases to destruction of the engine. Your engine needs a timing chain service, which replaces the chain, tensioner and pulley(s), timing chain guides, gaskets and seals. I would recommend having YourMechanic.com diagnose this issue, provide an accurate assessment of damage, and estimate the cost of repairs. YourMechanic.com can dispatch a mobile, professional mechanic to your location for diagnosis and repairs.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Volkswagen Polo 999cc Manual won't turn over/won't run

Hello, thank you for writing in. There are several reasons that a vehicle will have a hard time starting after sitting for a while. Most of the time it is related to a failing battery. Although you have tried to...

Q: oil leak

Hi there. First off, I'd recommend not driving the vehicle further before it's inspected and repaired. It's likely that you've damaged your oil pan or a primary oil supply line. The knocking is caused by low oil, essentially metal to...

Q: Car shakes while in idle and doesn't want to accelerate

The spark plugs are wet from trying to start the vehicle which is a good sign because this means that the motor is getting fuel. When the motor struggles to idle, this is generally a result of things like low...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...