WHAT IS CARS PROBLEM ?

” 2003 Pontiac Grand AM GT ”

” Symptoms ”

Are a lack of power during the day

it gets to the point to where I lose MPH when going up all hills and it takes a 1/4 mile to
get it up to 45 and longer to get it up to 70

it was quick just a month ago also as it reaches normal running temperature that’s when the power starts to lose it bad yet it runs better at
night until it gets warmed up again

I’ve had the service engine soon light come on a couple of times but it went out on my way home late at night. can anyone help?