New to tuning 07 trailblazer ss

[Kevin Brandenburg]

I got a buddy of mines 07 trailblazer ss he had another guy tune it for him and having problems here's the run down.

07 ss 6.0 chuck norris cam, long tube headers, cat delete ,2200 stall converter
Ran fine before cam swap, put new cam, lifters, timing chain, oil pump now it randomly misfires at light load , misfires over 60% throttle, but the weirdest thing is it goes into limp mode if you put it in reverse and back up a few feet the go back forward, Then you can floor it for a second and it goes out of limp mode. He has had it at trans shop thinking something when they pulled trans for converter swap but everything on their part seems to be good. No trans codes. He bought a replacement ecm to see if in the tune ( Tuner) wont seem to try and figure out problem. so I am tryinh to help him i have tuned a couple gen 3 dbc and did ok but this one has me stumped trying to figure out how to post the tune and data log

[Kevin Brandenburg]

07tb current running tune.hpt07 tb test drive.hpl

[Alvin]

Misfire diag stuff is unreliable after a cam and is normally turned off with a cam.

There is a OL fault in this. Scan it for codes... fuel trims are turning off when this happens.

You will need to tune the VVE on this.

[Kevin Brandenburg]

Only code is po300 random misfire , I also noticed no reading on maf except iat

[04silverado6.0]

I have no issues leaving the misfire diag enabled. I usually multiply it by a percentage depending on the chop level. It has saved me some time in the past leaving it functional. I mean generally a misfire can be felt but its nice opening the scanner to narrow down 1 burnt plug wire. Multiply all misfire detection tables by 2 for a start.

[Cringer]

Only code is po300 random misfire , I also noticed no reading on maf except iat

Do what Alvin says
OL Fault.jpg

[blindsquirrel]

DTC P0300-P0308

Conditions for Running the DTC

- DTC P0010, P0011, P0101, P0102, P0103, P0106, P0108, P0116, P0117, P0118, P0128, P0220, P0335, P0336, P0502, P1258, P3401, P3425, P3441, and P3449 are not set.
- The engine speed is between 650-6,200 RPM.
- The ignition voltage is between 11-18 volts.
- The engine coolant temperature (ECT) is between -7 and +130?C (+19 and +266?F).
- The fuel level is more than 10 percent.
- The antilock brake system (ABS) and the traction control system (TCS) are not active.
- The power management is not active.
- The transmission is not changing gears.
- The ECM is not in fuel shut-off, or decel fuel cut-off mode.
- Excessive drive wheel slip is not detected.
- Power Take Off is disabled.
- Cylinder Deactivation is not in progress.
- A manual transmission with a throttle position less than 95 percent.
- DTC P0300-P0308 runs continuously when the above conditions are met.