I have a 2001 VR6 VW Jetta, stock, that I don’t drive that much (70,000 original miles). It has a standard transmission and it is usually very fun to drive. I’ve noticed in the past year, however, that the performance has seemed to drop off a lot in terms of very slow acceleration. The power can be compensated a little by shifting at higher RPMs between 3800-4000, but it used to have that same power band between 3200-3500 even a year ago.
I know I had her tuned up last year & I had the best quality plugs NAPA sells put in her. The clutch has never been changed or reset (a mechanic told me VW has funky hydraulic clutches), but this seems to be some sort of engine thing, not a transmission thing.
Q1: If this is not ‘normal wear & tear’, where would you look first? Hoses? Seals?
Q2: If this is just age creeping up on her, are there changes/modifications that I could make or have performed to bring back the power she once had?
Hi & thank you for responding! No, the engine light isn’t on. Its not stuttering and there is no change in start up. I am letting it sit a week or so between start-ups though, but I don’t think that’s a factor. I am fueling her with standard gas and I’m using regular ‘dinosaur oil’, not the synthetic stuff.
I’m going to see if I can schedule a compression test.
It’s very unlikely that compression is low at that mileage in the absence of a more severe symptom.
A significantly restricted air filter or fuel filter could cause the symptom described.
Some modern engines can be really touchy about spark plugs, and can give trouble with alternative plugs regardless of their quality level. I always use the brand and number plug installed at/recommended by the factory. In this case I think you’ll find the brand is NGK. If that’s not what’s in it, it’s possible a change to the factory-type plug could help.
Putting a bottle of Techron fuel system cleaner in the tank is a long shot as far as helping, but it’s cheap, aids in maintenance, and might actually help.
If you end up taking it to a shop, try to describe the symptom(s) as accurately as possible. Performance dropping off over a year’s time is not sudden. Running great yesterday and running lousy today is sudden. Getting these details right often aids in a more efficient (= less expensive) evaluation of the problem.
Hmm I was thinking catalytic converter clogging up but that would generally throw a check engne light. Still might be worth checking though since a mechanic should be able to check it with a vacuum gauge in a few minutes.
Fuel fliter is a good culprit too. Generally clogged fuel filter causes power loss at higher loads.
I’ve never experienced it myself but I’ve heard it from plenty of motorheads about some motors being picky about the sparkplugs. I just use regular NGKs. they are cheap and do the job.
Air filter is something to check too.
Thats that weird narrow angle V6, right? I dont think that comes with a turbo or I’d say check for a boost leak.
Have you checked for a stuck brake? I had a Honda Civic rear disc caliper go bad on me once; it was like towing a piano all the way to the brake service shop. Obvious signs would be the distinctive smell of burning brake pads, and an abnormal amount of heat radiating from the affected wheel.