Car stalls when slowing to a stop!

[Pomps]

Hi guys

 

Has anyone got any advice on what my problem could be thanks? Its a long one haha.

 

I brought my 05 WRX Wagon about 2 months ago, and had this problem from the word go.

 

The cars revs drop nearly to 0 then jump back up when coming up to a roundabout or slowing down for a turning when i push in the clutch and down shift and brake, its mainly from 3rd to 2nd. Its has cut out completely and number of time and I’ve had to make the turn with no power steering or braking, it turn on again straight away no problem.

 

Its driving me crazy and kinda dangerous.

 

The car was completely stock when it had the problem and i wanted to mod it a little anyway, and hoping that something i changed may fix the issue to.

 

I thought it could be the MAF sensor! so i cleaned it with some cleaner, no dice. Checked for boost leaks, no leaks. So i thought it could be the IACV cleaned that as well as the throttle body a little, still no dice.

Then thought i would unplug the MAF and drive it to see, it drove perfect and didn’t have the issue at all, it did throw a code saying problem with MAF tho as it was unplugged. The car idles good but even better with the MAF unplugged, plugged it back in reset the ECU, still the same problem So i thought it must be a faulty MAF so order a new one.

 

In the meantime i upgraded the intercooler hoses, ancillary hoses added a catback exhaust system and panel air filter.

 

So the new MAF arrived, i unplug the Battery, popped in the new MAF, fully reset the ECU, let the ECU relearn by letting it idle for 10 min nothing on at all, then with the air con on full. Great idling good, good power, no misfiring.

 

SO took it for a spin with all my fingers crossed. And it still has the issue of nearly stalling when i brake and clutch to a stop.

 

This is making me go insane can anyone help? Don’t wanna take it to the main dealers yet to get ripped off.

 

Cheers

Pomps

[Gambit]

Hi mate welcome to S.O.C I'd have put money on maf :( 

Do you have a dump valve on it ? 

And does it just cut out or cough splutter then cut out ?

[Pomps]

Cheers mate.

 

Only the stock dump valve.

 

Revs just drop to nothing and cuts out. Its not every time cutting out when i down shift and brake to stop, but i look down at the rev counter every time I’m braking/clutching/shifting down to stop, and i see the needle nearly hit 0 then rev back up. Its like when you slow down less air is going in the ram scoop and the Maf doesn’t read it quick enough.

 

Was thinking it could be the dump valve not woking properly, could that affect how much air is being recirculated and the MAF reading? It is a stock DV tho. But why would the car run perfectly with the MAF unplugged? Could it be diaphragm in the DV sticking? Could it be the ECU?

 

SO stumped on this one.  

[Gambit]

Sorry for the delay getting back to you mate 

when you unplug the maf it goes into limp mode it's meant to be so you can get it to the garage or to a place to fix the car thats why it will run fine but it won't do the car any good as it might still over fuel the car. 

I had started to make a list of these problems not sure what I did with it so people could check them, as I'm guessing no ECU light and have had the same problem once myself know how difficult it is to trace the problem :( 

 

It's not common for a standard DV to go bad but if you know anyone local might be worth seeing if you could test one for the sake of 15 minute job :) 

 

I did buy a 2nd hand maf and still had the same problem I found cleaning them never worked for me either. So bought a new one solved my problem. With the engine running does it stall when you unplug the maf I found it's best to check when the car was already warm.

 

Split or loose vac lines is another common fault easily overlooked (I see you have done that) 

 

Give the Throttle Body a clean they get carbon build up and makes them run rough and stall

 

Fuel filter or plugs maybe when was they last changed.

 

I'd have a look at the fuel pump to make sure the connections are tight seen that before give people problems.

 

I'd give the ECU a reset too never know.

 

I would try the above 1st I will see if I can find that list I had. 

But I'd still say it was either a MAF problem or the TB need's a clean badly and the ECU reset :)