I am getting slight hesitation sometimes as I come on to boost, after a bit of research on here I wanted to eliminate the MAF and Lambda sensors. I have new coils and PFR6B's recently fitted.

I read that I can check the MAF by unplugging it and the engine should die. When I unplug the MAF the engine does not stall, but it does run rough (revs hunting). When I plug the MAF back in the idle becomes smooth again. Is my MAF ok or is it on the way out? If it is knackered do I need to replace or is it possible to clean it?

Also is there a way of testing the Lambda sensor??

 

If the plug gaps arent already at 0.6mm then that might be a cheap fix.

 

it does sound like a failing maf but the earlier ones are generally quite good mafs. Personally if it is running standard ecu then I would do an ecu reset and then disconnect the maf. It will probably stall.

 

They are at 0.7mm at the mo, will it make a difference if I reduce by a further 0.1mm?

 

So if I reset the ecu and then disconnect the MAF and it stalls, does that mean it is ok?

 

another vote..

 

Two top tuners advising 0.6mm, then 0.6mm it will be. I will update this thread to say if it worked or not. And thanks to everyone who replied.

 

Just to update, I gapped the plugs to 0.6mm as suggested, and cleaned the MAF sensor with brake cleaner. The hesitation has now gone