No spark changed destribator checked codes

Check for fault codes, check fuel pressure, check for spark.

What is year--make--model?
Are there any applicable trouble codes?
Make sure battery has a full charge and battery connections all good.
If the vehicle cranks good but won't start, the basics checks, 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 fuel injector pulse.
I give guys/gals the same info, don't know any other way.

When was You're last Tune up?
Check the Spark Plugs to make sure the Gap is correct. HC is unburned fuel ,Check the Air filter and Replace as necessary,If coil over plugs Make sure to replace the Boots on the coils as they have a tendency to Bleed and wont show a trouble code.otherwise Change the Spark Plug Wires this should Clear You're Problem

It's either no fuel pressure or no fire check to see if you have fuel pressure if not it could be the pump a stopped up filter or blown fuses the electrical side could be destribator cap or ignition module or coil packs or even the wires hope this helps

A PO305 code is for a Cylinder #5 misfire code. This would definitely cause a lack of power when passing and would cause the check engine light to blink when you are into the throttle and then stop once you let off the throttle. This could be caused by a faulty coil pack or a bad spark plug for that cylinder. I dont know which engine you have in this vehicle, but if each spark plug has its own coil, you can try unplugging the coil pack for cylinder # 5 while the vehicle is running and if it changes the way it runs then the coil pack is probably good, but if there is no change when you unplug the electrical connector, there is a good chance the coil pack is bad. It is not unusual for these coil packs to burn out.

Hope this helps... if there is anything further i can help you with, please feel free to ask.

Changing things is not always the answer. What were the codes?

CHANGE SPARK PLUGS AND WIRES .AND AIR FILTER.IF YOU SEE CHECK ENGINE LIGHT FLASHING ON.CODE SCAN SEE WHAT FAULT CODE YOU ARE GETTING.

CHANGE AIR FILTER.CLEAN FUEL INJECTORS.CHANGE SPARK PLUGS AND WIRES.BECAUSE MISFIRE CAUSE RICH CARBON MONOXIDE OUT PUT.MAKE SURE CHECK ENGINE LIGHT NOT ON IF SO CAR WONT PASS INSPECTION.CODE SCAN CAR SEE WHAT TROUBLE YOU ARE GETTING.

Bad coil ? Just a guess without seeing it but it's common.

SINCE RECOMMENDED TO CHAGE THE PLUGS, WIRES, AND COILS? HAVE YOU DONE SO? OR EVER?