Car Doctor Q&A: The Case of the Vibrating Volkswagen

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This week, Car Doctor John Paul diagnoses a 1.8-liter Volkswagen with an intermittent case of the shakes. 

Q.  I have a 2005 Volkswagen with a 1.8 liter engine and some days it runs great and other days it shakes and the check engine light comes on. I love this car and it only has 54,000 miles on it. It has been to a local VW shop where they looked it over, tried a few things but still it has the same problems. The engine codes indicate that all four cylinders are misfiring and there is a lean fuel problem. I’m pretty handy as well and have replaced the ignition coils, cleaned the fuel injectors and replaced the spark plugs and still no change. I work on my Chevy truck and somehow manage to keep that running like a watch. Do you have any idea what the problem could be, I hate to give up on this car?

Volkswagen Jetta

A.   One area that is a fairly common is a failure of the PCV system. Unless you work on these cars this isn’t the type of PVC valve that you may be familiar with in your truck. It is a plastic part with a couple of larger hoses that connect to it. It also isn’t all that easy to see or replace and will take even a skilled technician about 30 minutes to replace it. When this part fails it will cause poor idling and random misfire codes.

John Paul is public affairs manager for AAA Southern New England. A certified mechanic, Paul tests dozens of new cars each year and also hosts a radio show on AM 950 and 550.