Hi, hope someone can come up with some idea of what is causing my misfiring.

I have a 2001 WRX Bug which threw up a CEL a couple of weeks ago. I plugged the car into the laptop and I had misfire codes for cylinder 1,2 and 4. I cleared these and all was fine until yesterday.

On the motorway a car was about to be boxed in behind a lorry so to avoid him panicking and doing something stupid I dropped into 4th to get past him in plenty of time so he had room to manoeuvre without me braking hard.

This caused the CEL to flash and stay on but it still drove fine. I got home and this time it was misfire on 2 and 3. I cleared these codes and again all is well.

Could this just be the plugs need changing?

 

Sounds like the Neutral Position Switch needs replacing, it`s a common problem.

 

Okay, would that not show up on the diagnostic or could it just be on the way out?

Is this an easy fix and where can I get one of these from?

 

Yeah, could easy be plugs mate. Start with the plugs and work your way back to the coil/ignitor.

 

Not sure about diagnostics, but it will throw up misfire codes when the engine hasn`t been misfiring. I got a genuine replacement off ebay for abour £35, takes about 15 mins to fit on left of gearbox. Make sure you get the 5 speed version for your wrx, as the 6 speed ones are diff.

 

Brilliant thanks, I think I will replace that as I've read a fair few threads that have mentioned these failing. I will replace the plugs too and hopefully that should be a help.

 

Does the car feel like it's misfiring / stuttering or does it drive OK and it's just the CEL that's lighting ?

Shaun

 

I must admit that sometimes it does feel like it's stuttering but the CEL doesn't come back on.

I did try a very slow acceleration earlier and it didn't feel very smooth.

 

Is it a WRX or an STi ??

NPS faults on the WRX throw up misfire CEL's and on the STi the NPS interferes with the AVCS........

Shaun

 

It's a WRX. So does the NPS cause the juddering?