Gmc sierra vortec is out of time my truck acts like it has no power i have no timing light i was told there is a way to set the timing with out the light what do i need to do

What year motor Does it have a distributer or what

You can\'t. GM did away with timing light based ignition timing on the vortec engine family. You can adjust the distributor, but it adjusts something called Camshaft Retard Offset, and can only be read using a scan tool. The only reason you would need to check the camshaft retard offset is if you removed the distributor or intake manifold and accidentally got the distributor off a tooth or two.

the cpu has found sensor/s that are outside set parameters. have the fault codes read and replace found faulty sensors.

Check all your vacuum hoses especially at the PCV coming off the valve cover it is often over looked. The PCV fits loose either put a new bushing in the cover or add some black tape to the PCV at least until you figure out that might be the issue. Also your timing should be at TDC or 2 degrees plus or minus. Contrary to popular belief You can use a timing light you can see the timing mark know about where it is and line up the fly wheel mark accordingly.

Clean off the crankshaft pulley at the front of the engine and put some paint on the timing marks. Start the car and turn off any accessories such as climate control, lights and the radio. Start the engine until it warms up.

Connect the timing light to the battery and then to the number one ignition wire. Locate the assembly line diagnostic link also called an ALDL and use a jump wire to connect the diagnostic terminal "B" to the ground terminal marked "A". The ALDL is located under the left side of the instrument panel. Not all models of the GMC Sierra have an ALDL.

Point the timing light at the crankshaft pulley to verify the need for adjustment. Adjust the timing by loosening the distributor mounting bolts and turning the distributor until the crankshaft timing mark lines up with the middle line of the timing light

Tighten the distributor mounting bolts and recheck the timing. Remove the jumper wire from the ALDL with the engine running. Turn the engine off and remove the tachometer and timing light. Reconnect the number one ignition wire.

On the drives side long the fire wall on the harness, will be one wire from all the other ones, it could be brown or tan, disconnect the that wire, start engine and set timing, turn engine off reconnect wire and check timing again, should be advance now, also some times that will cause an engine light to come on, just disconnect battery for 15 sec. and computer is reset.

4 DEGREES BEFORE TOP DEAD CENTER UNLESS SPESSIFIED ON TAG UNDER HOOD

You can set the timing but the ecm, engine control module will reset it back to specs. So it useless to try. Good luck dont forget to rate

I AM LOOKING AT TIMING ISSUES OR INTAKE MANIFOLD LEAK.OR EGR VALVE STUCK OPEN.

Try a new distributer cap and rotor button before you go any further.