Jem

After sitting all winter My 2001 Mustang GT will not stay running. What might be the issue?

go-part

Fuel, spark, compression.

When was the last tuneup?

Does the car run with your foot on the gas pedal?

Red8310

Could just be bad gas

fastbackford351

If you left the untreated swill that passes for gas in the tank all winter, that'd be my first guess.

Vertigo_GT

There is an interesting and heated debate on Gas degradation and loss of octane during storage over in the 2005-2013 forum.
The consensus is that one of the debaters is a bloviating jerkoff.
Read and decide. https://mustangforums.com/forum/2005...related-2.html

If your getting spark and the car was running good when you parked it, I seriously doubt it's a compression issue. Soooooo

As go-part pointed out, one of the below is going to be deficient.
Fuel, spark, compression.

FlamingoGT

I noticed you didn't say which one you thought was the 'bloviating jerkoff'.

Vertigo_GT

Well, push come to shove, I'd have to say it's the self proclaimed expert on everything who compares himself to Jesus and blames the OP who asked if gas loses octane over time for causing him to expose his "A-holiness".

The OP didn't mention any CEL or codes. I'm an admitted rookie taking shots in the dark here but I'm betting on bad fuel or fuel pump with the most likely culprit being the fuel as others have said. I'd start with the easiest/cheapest. Check the spark plugs and gas. If there isn't too much gas in the tank I'd siphon off most of it and try putting some octane booster/injector and fuel system cleaner in the tank with some fresh 93 octane gas, and if it will run as long as you give it some gas pedal, run it a while to get the booster/cleaner and fresh fuel into the fuel system to see if that resolves the problem. If there is too much gas to siphon off,(where to put it if you don't have 4 five gallon cans?) same prescription without siphoning but use more octane booster?