Hi,

I have a missfire in my lt1. Its too rich but with the maf disconnected its run much better. My question is when the maf is disconnected the O2 sensors still working??? I am planing in buy new 02 sensors to see what happend. This is a good idea ??? Or should have a problem with the maf ??? Also with the maf connected, it works fine for 5 min and then comes the missfire again.

 

The only thing that happens when you disconnect the MAF sensor is that the PCM defaults to the speed-density method of calculating mass air flow. Everything else, including the closed loop feedback from the O2 sensors remains the same.

Have you tried cleaning the MAF sensor? Is it possible its coated with oil from the K&N in your Moroso CAI? Are you sure it is installed in the correct direction?

 

Yes, I allready cleaned with MAF cleaner. And it is installed in the correct direction. Also I changed the fuel filter.

 

Keep in mind the type of problem. First if it's rich, a bad filter would not be the problem. It would cause a lean condition if anything.

Missing can be both lean or rich. Rich could smoke but lean would not.

Anything having to do with AFR should show up on the O2 signals. Watching them and fuel trims should give an indication of where to go. After you replace the plugs.