RamLS1500

Ok I’m stumped and need some other opinions

I’m working on a 99 5.3 lm7 truck for a friend of mine and he just had a Howard’s rattler cam .525/.525 lift 109 Lsa installed BTR 5.60 stock lifters stock pushrods new head gaskets

The truck will start and run but it idles and sounds like a tractor

I have tried messing with the tune to see if I could clear it up and no matter what I put into it doesn’t change even asked other tuners for advice and had no luck so I have verified cam was installed correctly dot to dot confirmed and was installed at #1 cylinder at TDC I have checked coil packs injectors all the engine sensors and everything I could think of and have found out there is exhaust pressure coming out of the throttle body when you rev the engine up your can hear and feel the pressure pushing out of the throttle body and that is a first for me so any help at all will be greatly appreciated and thanks in advance !

VandykeT/A

EGR stuck open is the only thing I can think of.

G Atsma

Swap coil harnesses, as said in the OTHER thread you posted the same question in.

WE TODD DID

iTrader: (2)

Intake valves are staying open. Bent intake valve(s), pushrods too long, etc.

1FastBrick

iTrader: (16)

X2 Agreed!