Hey there

Just starting to troubleshoot this and am hoping for some more experienced folks to provide some direction :-)

It's a '98 Pontiac Grand Am. The car is losing power on hills. It also sputters when shifting gears as if it wants to stall out. Sometimes at stop lights it stalls and won't start again. Sometimes it starts back up.

Any ideas on where to start? Sounds like a fuel delivery issue, but that's just a guess.

Thanks!

We are talking about an automatic right? Next time this happens, before the engine stalls, shift into neutral and see if your engine idle normalizes.

Its a shot in the dark but it sounds like your engine is having trouble overpowering the torque converter when you are stopped. Which in that case means the engine is having trouble delivering enough power and that can also be the cause to your other issues.

My '78 did this when I played with the idle and I accidentally set it too low, the engine wasn't putting out enough power to resist the stopped torque converter in the transmission which would cause it to stall as soon as I put it in drive. My guess the reason the car won't start again is the same situation.

Does it do this when you get in the car and have it in Drive at home?

Check the idle RPMs. Also try to see if the idle is constant or if it moves around.\

I could be completely wrong, because I don't have an extensive knowledge about cars or engines, but I do have a good sense of intuition and logic.

First things first, I edited your OP so it's readable on the mobile versions many of us use. It was just a big blank white page.

Alright, to me, it sounds like a combination of dirty, possibly bad injectors and a clogged catalytic converter. The fuel pump giving out, chances are the car wouldn't have started up again.

What engine is in the car?

Does it happen all the time or only after the car is fully warmed up?

Any check engine light? get it scanned for codes

tighten up that throttle cable. lol.