Tach jumping?

[912091]

At idle my tach jumps 3-4 hundred rpm. Ignition is all new and so is the iacv. atr chip, 160 and a k&n cone

 

[GM TURBO]

Pull the ECM B Fuse for a couple minutes.

Plug it back in.

Start the truck.

Let idle for a few minutes without touching the gas.

Turn on lights, AC and any other accessories to allow the computer to make any adjustments needed with the system loaded.

Run Datamaster/Diacom and see what is going on.

Replace fuel filter.

Check fuel pressure.

 

[912091]

if i turn the ac on my truck dies fast

 

[GM TURBO]

Interesting.

Check vacuum lines?

 

[Loeryder]

Tach Dance = Ignition problems.

If it jumps around while "feathering" the pedal you have igniton problem.
Check for cracked insulator on one of the plugs or a wire not hooked up right or bad wire out of the box.
it all has happened before.

just have to narrow it down.

 

[912091]

I have replaced the plug wires 3 times and that dont work