I have a pontiac firebird with engine 455 With auto transmission. When I am naughty and push acceleration pedal fully, my car run very well but when the gear want to shift from one to two suddenly the

Ooooooohhhhh, I’m sorry but my question was complete I don’t know what happen. Anyhow my rest of question is as below: When I am naughty and push acceleration pedal fully, my car run very well but when the gear want to shift from one to two suddenly the engine going to die then I have to release acceleration pedal to half and gearbox smoothly shift to two. When I drive in city normally I don’t have any problem my problem is when I push acceleration pedal fully. In addition I feel when my engine and gearbox reach to working temperature I face this problem. I don’t use my car too much maybe I drive it 50 km per month. I didn’t have this problem 6 months ago

Perhaps a gummed up fuel system. Take the car out for a 200km drive and run a tank of gas and Techron through it. It may need a tuneup as well.

i cleaned my fuel tank last year and changed all fuel pipes between tank and carburetor. In addition i overhauled the carburetor last year. i renewed my distributor and spark plugs as well. But i agree with you that there is some problem with my fuel system. i want to inspect my carburetor fuel filter and then clean my spark plug and i let you know about the result for further advise