i have a 1985 12a carburated, all stock. So here is my problem. i first start up my car and it runs fine, idles fine accelerates fine. then once it is close to temp when choke shuts off it decides to shut off. then when i start it back up it sounds like a snowblower. almost as if it is running on just trailing or leading (only one set) plugs but im not exactly sure. it doesnt stay running unless i hold the gas pedal. also when i start to go up in rpm it will start to backfire when around 5-7k. can anyone help me please. in desperate need of some spirited driving. also its about 33 degrees where i am and i still have 15w-50 oil. i dont think that would cause this because i have had the same weight in last winter. the only thing i changed from ast year to this year is octane of fuel i started using 92 instead of 87. should i switch back to 87? please help

 

sounding alot like a carb issue causing it to run on one rotor when the choke opens. have u tried, while keeping it running, pulled the choke back out to see if it would keep running? may had some trash from the tank get thru and it's lodged in one of the passages.

 

i let her sit for a while and went back to start her up nd she ran shitty choke on then i cut the ignition to backfire and still ran shitty i let her die out then i tried again fired right up and ran fine i went on about a 20 min drive and then went and put some 87 in then drove around with some spirit and she continued to run just fine. this problem seems to happen intermittently more or less when shes in a bitchy mood as i like to put it

 

Where are you located?





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have you recently messed with the idle mixture settings or timing?
when was your last tuneup?