3B poor running - pretty long

Mihnea Cotet mik at info.fundp.ac.be
Thu Sep 26 21:14:29 EDT 2002

Fellow listers,

After running more or less ok for about 1000 miles, the 3B started making
troubles... so as an introduction note, I'll tell you that I'm running the
engine NA (more or less) with the WG spring removed because of the MM hose
leaking under boost. It ran fine but then yesterday started sputtering when
floored (or everything else past 1/2 throttle) but revs otherwise fine if I
back off the gas pedal and then press it less... Me thought of a bad oxygen
sensor first so today I got to pull the codes and here is what I got with
the explanations according to Mr Mockry (thanks again for your website

Air Mass Sensor ,
Open or short circuit, defective sensor, system in limp home mode

Oxygen Sensor Control Limit exceeded,
fuel pressure too low or too high, intake or exhaust leak, defective
ignition system component,
intake air leak after air mass sensor, O2 sensor is faulty
Symptom: CO before catalyst is below 0.3% or greater than 1.0%,
Extremely lean or overly rich exhaust, Spark Plug fouling,

So the spark plugs are indeed black as hell, and so are the tailpipes on
the inside.

What's weird is that after removing the MAF sensor's connector, the engine
really got into limp home mode and started to idle at about 1100 or 1200
RPM, which otherwise it doesn't do... so after clearing the codes and
letting it idle for 10 minutes this fault code didn't show up again, but
after a short test drive it was back on...

So what the heck is up with this engine? I guess the O2 sensor might need
to be replaced because I'm pretty sure it's still original at 110k miles
but would that alone explain the poor running? Could the O2 Sensor be
really bad? I didn't have the chance to test it before it was dark so I'll
do it tomorrow I think.

Thanks for any input in advance!


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