Starts hard when hot - 1998 Pontiac Sunfire

You really should have said what times you had problems.. Just saying at times does not help. If the engine is hot and is hard to start you should look at the heat shield between the exhaust and the starter. a hot starter = hard to start. ALSO if your timing is advanced it will cause it to be hard to start. also if your battery is weak.

Is the base fuel pressure the same hot when it is cold, and so is the spark weak when the engine is hot ?

Have the fuel pressure tested hot and also the engine coolant sensor tested for correct reading when hot.

check your fuel filter see if getting right amount of gas

before you try to start her again in hot weather, open your fuel filler cap, listen for any pressure release, close the cap, and try to start, if this works,then its just heat expansion in the fuel tank, replace the filler cap if this is the case

Might be an oil issue. Oil when hot might be too thick for the pump to pump the oil easily in the engine. Check that and if not that come back.

I think it may be time to change the spark plugs and wires.

have you check your fuel filter. and how hot dose the motor get when it start hard.no motor like to start when they are hot. check your fan relay. and check your coolnt ok. good luck have a nice day

I would focus on what's making your car hot.... a bad catalytic converter sounds like what you have...It's before the muffler..It gets clogged up...makes car run a little hotter and harder to start....Google it

Ignition module.