Buick Century Intermitten Chugging

Have a 91 Buick Century w/ 177k miles. Recently had crankcase senory and ignition module replaced. Driving the car on Friday was fine for the first 100 miles than filled up with gas and the car chugged until it gets up to speed. Same thing on Sunday when coming back home. Thought it might be something with filling up with gas - so took off the gas cap. It was then worse and actually die twice within a hundred yards of taking cap off. Put cap back on and worked fine. Help?

Could be a clogged fuel filter,fuel pump going out, or a number of things, electrical or mechanical. I’d start with changing the fuel filter first if it hasn’t been changed in a while, the move onto checking the fuel pressure. You’ll need a gauge or have a shop do it.

Thanks. I should have said I replaced fuel filter. I thought about the fuel pump. Is the gas tank being full or taking the gas cap off just red herrings?

Gas tank full or gas cap off won’t cause your car to chugg. If the fuel pump checks out good, you might look towards the tcc. Disconnect the torque converter clutch plug and see if driveability changes. It could be tps, MAF, or any of a number of sensors that haven’t gone bad enough to set a code, but are acting up.