recently i came back to my car after excessive rain (the rain may be coinsidental but i originally thought this to be the course). when i first fired the car up it appeared to be misfiring, was impossible to get above 2000-3000 rpm or keep the revs even, after hopping round the block a few times, the problem cleared.

 

now if i start my car from cold it runs like crap until it is warm, but then it stammers and misses bellow 2500rpm, the idle is also flutulating from 500rpm to 1000rpm and also sometimes stalls.

 

if i park up after a run and restart the car whilst still warm i sometimes gt a bit of missfiring and also runs poor as above.

 

I have carried out the ecu diagnostics which returned no fault codes ie 55.

 

i then carried out left and right lambda sensor tests, for both sides i got the same result, the check light stayed on for 20 secs or so at 2500rpm then flickered then back on for 20 secs or so.

 

I have also noticed the car to be eccessive on fuel for a while now, but i put this down to the exhaust which has recently been repaired. the exhaust was previously blowing in 4 gaskets so i had it welded into a complete pipe from centre to back box, it also has straight through pipes from manifold to back box and no balance pipe.

 

could the exhaust be the cause here or is this lanbda sensors, it seems strange for them to both go at the same time?

Maf?

so if my air flow meter was faulty it would cause dodgy readings on lambdas?

 

could this be from poss damp in air filter?

got no fault codes from ecu check

Do you have stock air filter, or induction kit? If you have induction kit, which one?? That could be your fault in wet weather.

its a blitz iduction kit, its been rather warm here for a week or so but still playing up, could it be damp is stuck in the maf? can this be resolved or do i need another, is there anyway of checking the maf with conzult as the ecu check brought up no faults?

Only real way is to swap a known good one and try that ;)

sounds like the cars over fuelling. Could be the MAF.. Do you still have the stock ECU or is it a chipped version??? has the ECU been remapped at all?

MAS - try a known good one. Of course it will show up on the O2 sensor test - they're actually telling the truth, the ECU isn't fueling correctly due to the MAS reading being wrong and they're telling you that ;)

Induction kits are prone to picking up excess water when heavy rain or otherwise damp and this can fubar the MAF. Another one of these mod induced faults which stock Zeds don't suffer from (we suffer from enough already :D )

its a stock ecu. its been awhile since any rain or damp but fault is still there. I know the car is well overfueling just a case of why. I have disconnected the maf to see what difference it makes and the car ran really crap and wouldn't go above 3000rpm, so the maf is functioning, but wether it is functioning correctly i'm not sure. I have also wondered if this could be the coolent temp sensor shot and the ecu thinking the car is cold all the while?

does the car rev above 2500 or just bounce about that figure ?

when the maf is connected it does do, without the maf it wont

 

its not possible to keep the revs in one place anywhere bellow 3000rpm, above 3000 the car runs fine.

 

this is even more apparent when the car is cold, but is also there when hot but not as survere.

 

the lambda sensor test suggests that the car is running rich and there is a obvious increase in fuel usage

just a quick follow up

 

this turned out to be a faulty air flow meter, cost £117.50 from zed world or £450+vat from nissan! but if you live in texas its $468 (£230) from nissan?