Not much info to go on. Ask a trusted mechanic in your area to diagnose it for you.
how to start a 1993 chevy tahoe without a key
That means that the computer system has recognised a problem with the emissions system on the engine or transmission. The FIRST thing you need to do is to have the computer system scanned with an engine scanner to find the area the problem may be in. Some parts stores will do this for FREE. Don't start replaceing parts. Have it scanned FIRST.
A faulty fuel pump will make a 1996 Chevy Tahoe hard to start after it sets for a few hours. The pump can allow fuel to leak back into the gas tank and starve the engine for fuel.
sometimes after a few trys it will start on it's own.
Turn key on ( do not start ) then push the gas pedal all the way down 3 times and then turn key off and then start the engine.
Does it have fuel, spark, compression?
It has chewing gun in the engine
do you mean it cranks, but will not start?
Maybe your fuel pump
Turn key on ( do not start ) then push the gas pedal all the way down 3 times and then turn key off and then start the engine.
A bad EGR valve should not cause the engine to not start. There is most likely another problem that is causing the engine to not start.
There can be many reasons why a 1997 Chevy Tahoe will not start after sitting for three days. Reasons include a dead battery, a bad starter, a bad alternator, a loose wire, and no gas.