No need to if the distributor was not moved.
you need to reset the timing the distributor did not go back in correctly
If the distributor has not been moved the timing will be as it was before.
It is electronic controlled and requires an OBDII engine scanner to set the timing if it has a distributor. If it don't have 1 then there is NO adjustment for the timing. You did not give the engine size.
cam timing will not change ignition timing i would try 8 or 10 degees advance at idle with the vacuum advance disconnected.
Assuming you did nothing to disturb the timing it would not have to be reset just for changing the head gasket.
A 5.7L with the IAFM intake it has a low profile distributor cap with the wires coming out the sides. (A traditional distributor has the top post outlets for the wires.)Those are set up with a "Net Build" timing system. There are tools fron K&D that flash a light but are inaccurate. You should take it to the dealer to have it timed.
There is no adjustment on the timing, It is controled by the computer. If you did not have the distributor out then there is no reason to worry about the timing, Unless the check engine light is on and you had it scanned with a engine scanner and it said that the timing was off. You will then need to hook scanner up to engine and go into the timing mode and move the distributor until the light goes out. Then tighten dist. and the computer will do the rest.
If you have put the distributor back in the proper position and its not out a tooth you might try to disconnect the battery for a few minutes (5-10 to be safe) to reset the computer. I really think you're out by a tooth which has changed the timing though...
to reset an injector , is a specialist job if injector is faulty, it needs replacing
seems that the timing is still incorrect. the distributor may be worn and causing this.problem may also be the points, a crack in the distributer cap,
The timing is set with the aid of a scan tool. It can not be done with a timing light.The timing is set with the aid of a scan tool. It can not be done with a timing light.
Purchase the shop manual for your vehicle, it will save you money for this job and many more repairs.