Engine stumbling at idle and hard acceleration

Have 98 filled tank and now after driving about 60 miles and shut off...came out started up now has rough idle and could hear popping in exhaust under acceleration...put in fuel system cleaner seems to run ok under lite acceleration but still popping under hard acceleration... don't know if I have bad fuel or injection problem...any ideas?

I would try some water removal treatment. Like HEET.

Well I used Lucas fuel system cleaner...was going to get gas down to 1/4 tank (@1/2 tank now) and put in fuel from different station...if that doesn't work I'll try heet....one thing to add... outside temps now in teens lows below zero.. wondering if that might have something to do with the problem...

I saw you're in Michigan, that's why I recommended the HEET..

I agree with aleekat, you may have freezing water trying to clog your fuel filter and leaning out your fueling, Heet will help that situation.

Put in heet with fresh tank of fuel...ran a little better, but still have problem... gonna have new fuel filter installed...(since temps here aren't gonna get above 20 degrees here) and see what happens... hopefully not intake... thanks for replies...

I had to replace the fuel filter on the big fuel pump here on the dump truck yard, must've been clogged with slush, added new filter and full flow resumed.

Well sprayed carb cleaner around intake while running and no vacuum leaks...but when starting cold engine if I let fuel pump run for about 10 seconds before cranking it fires right up (pump doesn't get up to full pressure) and when stopped put in neutral truck runs better.. going to get filter changed this weekend.... pretty sure that is problem...will post after I get filter changed

Well truck is fixed... took to Bell tire..what a mistake...they first said there was to many codes to find problem...then when I picked it up they said they couldn't get their computer to read out and there was no printout...and mechanic said I probably need a engine... needless to say I won't go there anymore..I got a buddy to put his fuel pressure gauge on it ...had plenty of fuel pressure (55 lbs.) So for the hell of it I replaced distributor cap and rotor...alass problem fixed....(thank God the weather warmed up)... That was problem all along....hope this thread helps someone else...just some old school mechanics solved the mystery..

I'd go back and throw em under the bus!! Tell them to stick to tires.

Thanks for the update, I guess most of these cars could always use a tune-up.
Mine could use some plugs....blew a 91 on the sniffer (220 HC is the max).

I definitely learned a lesson...I guess the upcoming mechanics are depending on computers to much... Don't know how to diagnose vehicles the old school way... never go back to them even for tires...lol 😝 my truck is to old for their computer.. probably won't even register on it...lol