92 240sx auto - intermittently cuts out

[alexh]

Hi,

My 92 240 has a hesistation problem when starting out from a stop and it's slowly getting worse - a few times it's gone into a weird mode where it barely runs for 5-10 minutes at a time. When this has happened I noticed lots of black smoke coming out of the exhaust indicating a rich condition or failure of cylinder(s) to ignite. Interestingly though even when it's in this mode it idles fairly well. It's just when you give it throttle it barely runs.

I have gone through virtually every diagnostic procedure in the manual and everything checks out. My conclusion is that either an injector is flat open or cylinder(s) are not getting spark. The other possibility is that the ECU is failing. The car runs extremely well otherwise.

The good news is that the problem is SLOWLY getting worse so eventually perhaps it will be in fail mode all the time and I can diagnose it. At the rate things are going however it may be a year or more and it's little scary driving it in heavy traffic.

Anyhow, the reason I'm posting is because last week I got a check engine and I have never got one before. However, I think it's meaningless.

It's code 34, knock sensor. Would you agree that it's doubtful this has anything to do with the problem I'm having? I would imagine even if you unplug a knock sensor you would barely notice it.

Thanks

[MaximA32]

The knock sensor will not throw a MIL. It's simply a stored code. As for your other issues, check the MAF sensor and see if you're getting about 2.4v at 2500rpm. If not, I'd say you've got a bad MAF sensor.

[alexh]

Thanks, this is the kind of info I need. Manual says to check at idle only and it was within spec, but barely.

[alexh]

Thanks, this is the kind of info I need. Manual says to check at idle only and it was within spec, but barely.