Help needed ASAP. 99 4.8 in 94 c1500

[Wiregrass mechanic]

Maybe the maf isnt reading. Have you data logged anything

I cant datalog until new harness gets here Friday.

The customer bought a donor car and it was running. The person he initially hired of course made this swap 1000 times more difficult.

If anyone else has suggestions I'm open ears.

 

[Jglew82]

Have you tried unplugging the MAF and see if it runs and revs in speed density mode? Just spitballing at this point, but it’s an easy check.

 

[Wiregrass mechanic]

Have you tried unplugging the MAF and see if it runs and revs in speed density mode? Just spitballing at this point, but it’s an easy check.

When you unplug MAF it idle hunts up and down a few times when you try to throttle up it dies.

I greatly appreciate the suggestions. Another set of eyes (viewpoint) is greatly appreciated

 

[93crewcab]

You need a way to datalog and stop wasting time.

 

[Madscientist]

Acts like it has a DBW pcm in a DBC motor.

 

[HotWheelsBurban]

If it was a vortec that last symptom sounds like a throttle position sensor, cause that is exactly what mine did. But IDK on LS motors.

 

[Wiregrass mechanic]

I changed the TPS

Got new harness today. Had to modify couple of plugs. One was for the MAF had a 3 pin on harness needed 5 pin. And the o2 sensors where square needed flat ones.

Got those done today and old one back out. Will install and keep posted