I have a issue with a 5.3 where when it is revved w/ the pedal (forcing IAC open to raise the RPM using the hp tuners scanner doesn't create any problems, it only runs weird when raising RPMs w/ the pedal)

When I unplug the TPS, it runs very good, like as it should. Reving w/ the pedal everything is nice and smooth *when TPS is unplugged*

So, what does the PCM fall back on when the TPS is unplugged?

I suspect something is messed up w/ the tuning in that area, with a table that utilizes the TPS sensor to run the engine


(I've replaced TPS sensor, and it is showing normal values using HP tuners scanner)

 

Limp home mode = limited engine speed and trans shifting. The pcm will try and read engine needs from the other sensor=MAF,MAP,O2, Crank position,O2, trans speed etc. it will run but your gas milage will plummit.