I have a 89 burban 350 tbi 142,000 miles, that i pick up in Oct. I live in Ft Worth, Texas. Last week after it set for 3 days without me starting it. I could not get it running. I tried about 50 times to start it. It has a new battery,starter, plugs,wire,coil,dist. cap,rotor,fuel filter. It was cold (35-40 degrees) here. I took the burban to a shop and let it warm up in the garage and after a couple of hours she started up after about 10 tries. She backfired and flames came out of the carb. Once it runs it runs good. I check the timing and it's in time and it is getting fuel. I can let it set over night and it will run the next day after about 3 trys. Not sure where to start looking.