MAF sensor and boost question.
Discussion
I've got a 2002 WRX and occasionally, the boost will be slightly weaker than normal with some hesitancy. Also a little while ago I had a lumpy idle when it was warm - I put this down to a crap fuel batch at the time. It's always run on V-power though.
I'd say about 90% of the time it's absolutely fine, it's just a bit random.
Am I right in thinking that my MAF could just do with a clean? It's on 84k, so I'm pretty sure it hasn't had one in it's life!
Edited to add - It has a K&N panel filter, which I've heard stories of the oil contaminating MAF sensors, which also could be a culprit?
I'd say about 90% of the time it's absolutely fine, it's just a bit random.
Am I right in thinking that my MAF could just do with a clean? It's on 84k, so I'm pretty sure it hasn't had one in it's life!
Edited to add - It has a K&N panel filter, which I've heard stories of the oil contaminating MAF sensors, which also could be a culprit?
Edited by Hrimfaxi on Saturday 3rd September 23:02
a Maf won't show a cel , try cleaning it first , I use carb cleaner not ideal , and then see how car performs , they are not the cheap ones , I did find one on ebay for about 80£ or so , the newer ones tend to be more reliable , option 2 ask some one to borrow one and see how you get on , and yes k and n oil can cause issues
vxr2010 said:
a Maf won't show a cel , try cleaning it first , I use carb cleaner not ideal , and then see how car performs , they are not the cheap ones , I did find one on ebay for about 80£ or so , the newer ones tend to be more reliable , option 2 ask some one to borrow one and see how you get on , and yes k and n oil can cause issues
I don't have a CEL, but yeah will try to clean it first. I've got some electrical contact cleaner that I might try to use, I've read that's ok - give it blast and leave to dry before putting it back. Thinking about swapping out the K&N for a Green cotton filter too.
if you clean it I just put it straight back in , if after its cleaned it's ok for a while it may be your issue , but I expect if will re occour and need replacing in time , see how you get on with it , import car parts or a supplier , k and n is ok just don't over oil and just oil the side away from the Maf
vxr2010 said:
k and n is ok just don't over oil and just oil the side away from the Maf
this. i've used k&n's for decades with maf's and never had a problem. many folk simply over oil the filter. there's a proven trick here, pour the oil in to a small atomiser/spray gun and oil the filter. it always ensures a light even oiling without no over-oiling/excess oil coating the maf sensor/wire/internals 
Just to update as it's been a while!
I carefully cleaned the MAF with some electrical cleaner and haven't had any problems afterwards, but it did look a bit grubby, I suspect it'll return and I'll have to replace eventually.
As for oiling the K&N, the filter I have is relatively new, still has a light sheen of oil from the factory on it. I've used K&N in the past with factory oil a clean and re- oil and no problems then. Perhaps there was a bit too much on it to start with.
I carefully cleaned the MAF with some electrical cleaner and haven't had any problems afterwards, but it did look a bit grubby, I suspect it'll return and I'll have to replace eventually.
As for oiling the K&N, the filter I have is relatively new, still has a light sheen of oil from the factory on it. I've used K&N in the past with factory oil a clean and re- oil and no problems then. Perhaps there was a bit too much on it to start with.
that's good news , some times the Maf issue is the beginning of it not working as well , but if it's working I would not worry , I picked up one on ebay for a good price , it was brand new and in Subaru packaging , I'm assuming it was the real McCoy , the new ones from Subaru are pricy , there are US sites that do them cheaper
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