Fuel Car running horrible on 93

[1983foureyegt]

Hey I own a 1983 Mustang GT (carbureted) and decided to fill it up with 93 to see what would happen and after the 87 all got out of the fuel lines it’s been running horrible, I cannot accelerate fast at all . Will draining it and putting 87 fix that? It is also back firing out of the carburetor, it has never done any of this before Any help is a appreciated thanks

 

[jrichker]

It sounds like you got a load of bad gasoline. Drain the tank, replace the fuel filer and see what happens.

 

[1983foureyegt]

It sounds like you got a load of bad gasoline. Drain the tank, replace the fuel filer and see what happens.

Thank your for the advice I drained the gas and filled up with 87 and it’s helped a little bit but still bogs at top end and mid range some times, I ran through about half a tank of 87 , what should I do now?

 

[General karthief]

Change the fuel filter, it may have gotten some junk in the carb. Are you experienced at taking the carb apart?

 

[1983foureyegt]

Change the fuel filter, it may have gotten some junk in the carb. Are you experienced at taking the carb apart?

I am not experienced at taking the carb apart, I have the car up on Jack stands to replace the fuel filter and the weird thing is that there is no fuel filter in front of the gas tank where it should be, I don’t see one on the car anywhere

 

[General karthief]

Pull the fuel line off the carb,

https://www.cjponyparts.com/fuel-filter-5-0l-w-4v-carb-1983-1985/p/FG788/

 

[Noobz347]

It sounds to me like it's time for complete tune-up. I suspect that your ignition is breaking up in those ranges.

 

[1983foureyegt]

It sounds to me like it's time for complete tune-up. I suspect that your ignition is breaking up in those ranges.

I just had a eldebrock avs2 carburetor installed , new plugs , new wires and a new msd distibutor cap put on and it was running fine until I added 93 octane gas into the mix

 

[Wayne Waldrep]

So someone correct me if I'm wrong, but higher octane rating can't have a negative effect. I think the timing was just coincidence on that. So maybe put the octane on the back burner and focus on what's been said because there's some knowledge folks on here that will help get that problem solved. Keeping working on it! No pressure guys....

 

[Noobz347]

So someone correct me if I'm wrong, but higher octane rating can't have a negative effect. I think the timing was just coincidence on that. So maybe put the octane on the back burner and focus on what's been said because there's some knowledge folks on here that will help get that problem solved. Keeping working on it! No pressure guys....

It wouldn't have a negative effect because it was higher octane but it could just be bad gas as JR suspects.