Fuel filter and strainer were clogged up. Both had less than 20 miles on them. Gas tank has rust in it.

Here is a log of a 2nd gear pull and a 3rd gear pull

I've installed a new set of plugs and also tried my old gm maft. About to go do a boost leak test. Usually I'm able to figure things out but this has me stumped.

I tried a set of lightly used bpr9es and had the same problem. I will be getting a new set of plugs to try. When I've encountered problems like this in the past it always seems to be a boost leak or ignition problems. Not looking like either currently but I will get a set of colder plugs as well.

I'm sure I did. I have a spare

That is something I had considered. I do have my original gm maf set up. May try to swap it out. The wideband stays between 11.5-12 to 1 when the cut out and backfire occur. The car is just starting to make boost when this happens. I just installed the wideband yesterday.

I don't remember the specific's of this run. I may be varying the throttle to see if I could rev any higher. This log was over a month ago. I have spare parts from other cars. I'm sure I have a tps, although it has probably been sitting for a decade. I'll put another on. Thanks

Vegas smith, here is a log from about a month ago.

I have done probably a dozen boost leak test. I had the same thought as you. The boost takes almost a minute to drop from 20psi.

It will be a few days before I can get back out there. I haven't gotten very far with dsmlink but I will get some br7es and log a pull. The timing should be the factory timing map.

I was able to make several full pulls previous with the keydiver chip. Also does the same thing with dsmlink. The wideband doesn't go lean either. I may try adding some fuel and see what happens.

The car is a fairly new build although she sat for 4 years and is now being finished up. I'll give some info on the car when I start to list what has been checked and changed. The car had pulled all the way till redline and then during a pull I heard a pop at around 4200rpm's. There were a few...