Bad gas (gasoline) problem
 

I'm helping a friend with an 89 5.0 EFI Cougar that I think has stale gas. I'm posting here because I have always gotten great info from you all on this site and I believe the components of the system are all but the same as the Stangs

The car had been sitting for 2-3 yrs before he bought it. It was running when it was last parked by the previuos owner.
The tank was nearly empty and he put a few gallons of fresh gas in the tank.
It will turn over fine with the starter but won't fire or even sputter. I used a timing light and it has spark. The fuel pump runs for the normal second or two and then shuts off - so I think it has fuel pressure.
I'm thinking all the lines and filter have old gas/varnish or water in them. Since the engine wont fire I don't know if the old junk will push through so the new gas can make it to the injectors.

What is the best way to flush all this out of the tank and fuel system? A new fuel filter is a given, but it would be nice to get this thing running without having to tow it to a shop.

Thanks

Re: Bad gas (gasoline) problem
 

You can check for fuel pressure at the shrader valve. Did you pull a plug and look at it? I'd pull a plug just to verify you have spark at the plug. Before I did all that though I'd spray some ether thru the throttle body and see if it trys to start. I think even with bad gas it should still atleast sputter or something. Does the engine sound like it has compression?

Re: Bad gas (gasoline) problem
 

Another vote for Ether, then go from there.

Re: Bad gas (gasoline) problem
 

OK, I'll try ether and then move to plugs after that.
If it comes to life what is the best way to clean out any possible gunk that may be in the injectors?