2000 Monte Carlo SS Top Swap Commanded AFR Issue

[GTPpower]

Hey guys,

I'm out of ideas on this one. It's a 2000 Monte. It's running a top swapped L36, with the stock L36 computer. It's got a set of headers, and a N* TB with LQ4 MAF sensor.

Take a look at my scan and check out the WOT areas. Why is commanded AFR jumping around like it shows? I've got through the tune multiple times and can't find any issues. Any help would be appreciated.

Thanks.

[Bill@HPTuners]

The o2 sensor is jumping around from static to very low, that would be one of the first things I would check but I'm sure there are other issues.

[GTPpower]

This car has had lots of issues for the past few years. But, why would it matter what the O2 is doing while it's in PE? Is there a certain threshold where it will actually read from the O2 when in PE if it "thinks" the afr is bad enough?

[Bill@HPTuners]

If there are mechanical issues they will lead to additional issues. For instance if your tps is jumping around due to a bad tps so will your commanded afr. Fix the mechanical issues then tune, not the other way around.

[GTPpower]

I wasn't doing any tuning, just double-checking the tune I had on there, and scanning to see if anything threw some flags.

A little background info. He swapped heads and the supercharger onto the car about 2 years ago, and it's been misfiring ever since. Sometimes it's worse than others, and sometimes it won't misfire at all. It's a strange problem, because it's not consistant at all.

Up until now, I haven't noticed anything strange in the scans. In the scans I took on Saturday, the TPS looked to be working just like it should. I thought that would be the problem too, but according to the scans, it's working fine.

I know that he's melted some wires on it, and I'm not coninced that they are fixed. I think that's the issue, just checking to see if there's any other ideas.

[Bill@HPTuners]

Start with checking dtc's and fixing the o2 sensor.

[GTPpower]

Ok. Thanks for your help, Bill.