cut out at 4500 rpm

Hello I'm new to tuning so I didn't want to tune my sons chevy trailblazer, So we took it to a shop to get it done it seems to be running good other than a cutout at about 4500 rpm. I don't see any knock retard at the time of the cutout on the scanner. 2006 chevy Trailblazer ss stock engine internals, Magnuson tvs 2650 blower, flex fuel, return style twin fuel pump system with base pressure of 58 psi, one step colder spark plugs gapped to .028''.

attached is the tune file

A datalog of the issue occurring with all pertinent monitors would be a big help.

In the meantime, did it run fine for a period of time or did the tuner run into this issue on the dyno and stop?

What does the tuner think the issue is?

the tuner ran into it on the dyno we are still working together to figure it out he wasn't sure what it was. he is supposed to work on it on Wednesday, talking about working thru VE map.

here is a pull on the street 1st and second gear it had a small cut out on this pull about 5500 rpm.

Jose,

I see the misfire in this log, but it doesn't correlate with a change in fueling so at a glance it seems there may be a mechanical or electrical cause. Have you made any progress on it?

I’m looking into the wiring but everything looks good. It also doesn’t register on the misfire counter. And it doesn’t do it every time. And spark plus look good.

Got it. What spark plugs and gap are you using?

Ngk Br7ef .028

Thank you, that seems reasonable. Have you tried swapping in a known good set of spark wires yet?

The ones in it are brand new but I might try that next.

OK, I would also verify bypass valve operation if you have one, just in case it's cracking open occasionally and causing odd behavior.

Please keep us posted.