MAF sensor question.

[Enzed]

I brought a 99 golf about 3 years back. After about 6 months of running, you'd occasionally get very poor performance (very rough idle, crap accelleration, etc), but this usually resolved itself over a matter of days.

However, it's recently been occurring more often. Nothing seems to set it off, but it's a pain in the ***. After a bunch of investigation, I've narrowed it down to something like 'limp mode' being entered. Now, after some more info, I unplugged the lead to the MAF sensor, as apparently that can cause the issue. So, after a very shaky start one morning, it's now running better than with it plugged back in. So, I've deduced that the issue is most likely being caused by the MAF sensor.

My question is this. What's the friggin' point of replacing the MAF sensor? What pitfalls are the running my golf without it being plugged in?

[kenney]

#4 Today, 07:28 PM
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Re: Car just failed MOT, CO emmision issue

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The car cannot lambda regulate (to achieve the required Lambda 1 necessary for the catalyst to work) with the Air Mass Meter disconnected. Fit a new genuine Audi dealer sourced exchange AMM (DO NOT buy one from anywhere except Audi, no matter how tempted you are by fleaBay prices) and then have the ECU interrogated for fault codes. Have the codes printed out (including the one you have generated by disconnecting the AMM) and then have the codes cleared. Take the car for a good run (probably illegally now without an MOT) and then have the emissions re-tested. If the emissions are still too high, you will have to get another code read done and see which code (or codes) come up and compare this with the original code read and see if the same code(s) come up twice. NEVER even turn the ignition on with any sensor disconnected unless you can code read it first and clear the code you have generated afterwards.
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[phil miller]

its common place for the AFM to go down and give poor performance they dont always come up on a scanner and the best test ive found is to disconnect the AFM and drive it, if the car runs better then replace it, if you cant afford a genuine one go to GSF and get one from there, bear in mind they have 2, a good one and a cheap one, advoid the cheap one cos they dont last 5 mins

[TDiBoraSam]

Not advisable to disconnect the AMM then drive the car. It'll probably throw up confusing fault codes.

Also, don't buy a AMM from anywhere but a VW dealer. Anything other than a genuine one, and you're asking for trouble. I know only too well because I went down the non-genuine route to try to save a few quid and ended up having to buy another AMM in a matter of weeks.

[phil miller]

Not advisable to disconnect the AMM then drive the car. It'll probably throw up confusing fault codes.

Also, don't buy a AMM from anywhere but a VW dealer. Anything other than a genuine one, and you're asking for trouble. I know only too well because I went down the non-genuine route to try to save a few quid and ended up having to buy another AMM in a matter of weeks.

ive never had problems with fault codes but then i plug them in, GSF bosch afm seem fine ive never had to re-replace one