checking a maf sensor

how can you check a maf sensor and what are the signs that one is failing,

well you know what ours did hesitated and spluttered occasionaly.think ours had been goosed for a long time on the bug according to andy f,was sorted thanks to him and finn.

Unplug it when the car is running. If the engine cuts out the MAF is ok..

Read the fault codes, if its gone away from the parameter in the ecu it will log it as a fault, the problem is not all faulty MAFs throw a code up,the problem with MAF sensors is they can have an intermittent fault so can cause the engine to run fine 1 min an poor the next.

Best thing to do if you think you have a fault is borrow one from another car that is known good, a MAF from wrx or STI from 01 to 07 will work.

Thanks Jonny,
There’s been no engine light on but the code reader will not work on the car, I find that when the car is cold it hesitates and feels like it jumps,untill you build up the revs, when it’s warm it runs better but hesitates when you give it some juice.

Does anyone have a maf I could try before I buy one to rule it out?

Have you tried just the one code reader on it. I'm sure someone up your way will have one that should work

Hesitating on light throttle could also be lambda sensor.

Does it have any idling issues?

It holds idle but pops now and again sort of like a misfire and you can feel it through the car and the exhaust, if that makes sense

a sticking dump valve can cause these symtoms if you have an aftermarket jobbie fitted

the standard one is still on, iv just had a look at my plugs and the gap was, 3 plugs at .022 and one at .021 what is the right gap for the ngk 7h plugs.