I have an 02 WRX with full decat and SS Ecutek remap. Since refitting the ECU the car has become progressively more hesitant during acceleration. I’m convinced that this has nothing to do with the remap as it is a standard SS postal map which has caused no problems in other MY01+ cars. More likely the remap/ECU reset is highlighting an existing problem that didn’t show up on the standard ECU.

Anyway, once over it’s initial lurch(going from closed loop to open loop?)the car pulls well on WOT, with little if any hesitation. The problem seems to occur under partial throttle accel. The CEL came on a couple of times (flashed for a while before going out. Eventually staying on.)The select monitor shows that the ECU has logged ‘misfires’ on cylinders 1 and 3.

My initial thought was that the spark plugs were u/s or req regapping, but on talking to Pete at SS he suspects that as the problem is getting worse it could also be the front o2 sensor.

Before taking the car to my local dealer who knows even less than me. (it was the 1st time he’d used the select monitor!) I want to be armed with as much info as I can.

Has anyone had any experience with this problem or know of any other potential areas to check etc. I’d be most grateful. I don’t want the dealer costing me a fortune replacing parts unnecessarily or bulls!tting me(I believe 01+ lambda sensors cost a few bob!)

For info: Idle seems ok, fuel consumption is normal, boost is stable at 18psi.

If there’s any info I’ve missed please ask

Cheers

Pete's spot on.......though once the car is on a diagnostic as long as the dealer can scroll through the error codes page, it will give him all the necessary details and pin point the fault.

So why does a failing Lambda cause a misfire? Is the ECU not cabable of spotting a failed Lambda rather than waiting for another problem caused by the Lambda.

Is there a site/link I can read on all things ECU to save asking daft questions on here.

just use the search facility M8

The lamda controls the fuelling for the ecu, hence if its not reading correctly, fuelling can be all over the place....

When remapping is about to begin/done, usually readings are taken to ensure all sensors are working.

On many 99/00 models it has been found that either the maf and/or lamda have failed, or the remap has highlightened these areas.

Either way many tuning companies keep stock of the items as it is a common failure