Mass Air Flow Sensor

First off, I must admit that I'm relatively mechanically inept, which is why I find these forums a great resourse for the mental midgets of the world such as myself. Thank you for all your posts.

Anywho, I replaced my MAF sensor a couple of months ago. My 2001 Jetta TDI was sluggish and had little torque. After I replaced the part, my car was back to its old self. Yesterday, I was driving from Los Angeles to the San Francisco Bay Area and as I was accelerating up a hill I noticed that my car had a sudden decline in torque and that it was difficult to maintain high speeds especially when driving uphill. It was very similar to before I replaced my MAF Sensor.

My question is...do you guys/gals think that my MAF Sensor crapped out again? And if so, what am I doing to cause this to happen? I purchased the replacement part from TDIparts.com which was recommended from a buddy of mine who works on cars and has a TDI himself. It's a Bosch MAF Sensor, so I thought it could last a relatively long time.

So that's my dilemna. I look forward to what you guys have to say...

Thanks.

I have had three bosch units go bad and replaced them with the pierburg unit from world impex and never had another problem.

The problem could be any number of things. MAF, cloged intake, etc.... Does the power come back after you turn the car off and start it again? How many miles on the car? has the intake been cleaned? Look on this list to get in touch with a local TDI Guru to help you diagnose/fix the problem.

BugBug said:

The problem could be any number of things. MAF, cloged intake, etc.... Does the power come back after you turn the car off and start it again? How many miles on the car? has the intake been cleaned? Look on this list to get in touch with a local TDI Guru to help you diagnose/fix the problem.

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I have about 140k on the car, and I noticed yesterday that the cars is torquey again. I just replaced the inline air filter too.

Do you use a stock (VW) air filter? Aftermarket (especially oiled air filters like K&N) have been shown to shorten the life of a MAF significantly.

Next time your car goes into "low power mode", stop somewhere, put the car in neutral, and floor the go pedal. The tachometer should shoot up to about 5,100 RPM if the MAF is working. If it brick-walls at about 4,800 or so, the MAF is toast.

If you can still get to 5,100 RPM, then it is probably not your MAF going bad. It could be the N75 valve (which controls the turbo), a vacuum line, the VNT actuator on the turbo, fuel restriction, or some other cause.

If it turns out to be your MAF again, I would suggest using a good quality contact cleaner on the MAF and the plug. Although hard to find in stores, I highly recommend Caig DeOxit and Caig Gold. The first is their cleaner, the second is their contact lube and enhancer. Some Radio Shack stores carry these products, or you can buy them direct from Caig online.

Could be limp mode as well. If Intake is clogged especially!
If you use contact cleaner on the MAF, dont be suprised if you see lots of white smoke upon startup. Mine smoked really bad for about 10 minutes after cleaning the MAF.

i had a similra issue (see my other thread on lost power in top gear)...i just brought it to the dealer and they said the MAF is bad.

i questioned why there was no check engine light on and they say it may or may not trigger a code. others on here said it could have been the VNT actuator.

ill have the car back tonight...we shall see!

limp.

When was the last time you cleaned your intake?

Bad MAFs usually do not throw a code.

Thanks so much to everyone who replied. I love my TDI especially when it runs smoothly. Having all of your brains to pick helps me do that, so thanks again.