I have a 99 chevy blazer will not start weve checked fuel pressure and spark at the plugs we checked the timing with a lite and its correct can u help

Have a helper crank it, while you visually check for spark at the spark plugs. If spark everywhere, use a gage and check proper fuel pressure. Also, check for a fuel injector pulse.
Can you check applicable trouble codes? To check codes, yourself, at the least, you need an obd2 code reader.

Is there a security lite on the dash? Is it flashing or anything?

Fuel pump relay on fire wall or furl pressure regulator

If you need further help, reach me via phone at https://www.6ya.com/expert/justin_f1b4194bdc162d2e

Run basic tests--Spark to plugs? Correct fuel pressure key on? Compression?

Check the MAF sensor, is it dirty?

Check your fuel pressure, if low or no pressure, replace fuel filter first. My guess is the fuel pump and sensor are bad. You may also want to see if your getting spark, but I don't think bad plugs would make has gage jump around, but if they are not sparking correctly they will allow gas to flood the motor and that's when you get the gas smell

It needs at least 60psi fuel pressue to start. You need to check fuel pressure with a gauge.
If the dist cap or rotor is bad, the spark will not be on the right plug at the right time. Same goes for a faulty distributor or a problem with the timing chain. And the ignition module.
Also check the ecm for trouble codes.

take nomber one sparke plug out and tape a paper there turn the motor over 3-4 times if the paper is wet then you are getting gas if not it could be an injector try some fuel cleaner in you gas

CHECK BATTERY VOLTAGE FIRST IT SHOULD BE 12.5 VOLTS.IF NOT REPLACE BATTERY HAVE ALTERNATOR CHECKED.IF BATTERY GOOD.HAVE VECHICLE SCAN FOR PCM PROBLEMS - CRANKSHAFT SENSOR PROBLEMS OR CAMSHAFT SENSOR PROBLEMS.IF ALL IS GOOD GET A SPARK TESTER AND FUEL PUMP PRESSURE GAUGE TESTER.IF GETTING NO SPARK PROBLEM COULD BE LOOSE BAT.POWER SUPPLY WIRES AT IGNITION COIL MODULE OR IGNITION MODULE FAULTY.IF FUEL PUMP NOT RUNNING CHECK FUSE ABD RELAY IF BOTH IS GOOD FUEL PUMP FAULTY.

Looks like you've covered the basics, make sure the firing order is correct with your spark plug wire replacement. Hope this diagram helps.

THE FUEL PUMP IS BAD.

if your losing fuel pressure after the pump runs the drain back valve in the pump has failed.

and i doubt that you are seeing enough fuel pressure to run a vortec engine.

low fuel pressure equals a non running vortec