Sorry for the silly question....

I have a 94WRX Import

I trying to fix a misfire/hesitation at around 2-3K revs - only happens when warm and goes when the you accelerate - I have a good hunch it the Lambda sensor (already changed the coil packs and cleaned the boost valve)

I understand I have two Lambda sensor - I've not looked but I think I have one at the near the manifold and one mid way along the exhaust

Questions
1. Which one should I replace first?
2. I would to find a supplier today so I can fix this weekend - I'm working away so cannot look at the car - What sensor would I need ? (2,3 or 4 wire for a 94 WRX import)

Cheers

 

When you say boost valve, do you mean boost celinoid (sp) ?

 

It will probably be in the header on an early WRX - look under the front bumper on the driver side.

One in the cat is to alert you to it being on fire, and isnt a lambda sensor.

Later cars have the lambda in the downpipe.

Think you mean the dump valve too?

MB

 

Sorry - Yes boost solenoid was cleaned...

 

Is your idle erratic and fuel consumption worse than normal?

MB

 

Idle is smooth

Fuel consumption feel as though it is up - although I don't check

Last MOT - the guy said it was running rich

 

Could also be the maf or an air leak too. Plugs replaced? Unusual to be the maf on an early car though - 99/00 are the bad actors.

MB

 

Already checked for air leaks.

Do you not think it is the Lambda/O2 sensor?

If the MAF - Then the idle would be bad - Yes?

Plugs replaced with coilpacks 3000miles old

After changing the packs the cars was fine until a few weeks a go and has been getting worse.

 

MAF or lambda can cause poor idle - more likely the lambda though.

If you can check its voltage at idle that will tell you - should bounce from 0 to 0.8v back and forth - but it sounds like it is at fault.

MB