not to be mean but there isn't many. i suggest that you get rid of that car and buy a more reliable car.
Not without some major modifications, and I do mean major.
Your best bet is to check prices on some of the big box parts store's websites.
"There are tons of upgrades for these cars. Some include: trim upgrades, headlight upgrades, fuel return pipe upgrades, as well as transmission upgrades."
It depends on what engine you have. On some you have to remove the housing on the top of the engine which contains the coils etc.
Some cost effective upgrades would be an air intake and upgraded exhaust. You can normally find good deals online.
Short answer, NO.Long answer. Torches, welders, and some scrap steel make anything possible.
Vaulting items are a good way to get upgrades. You cab get bonuses such as +6 energy, +2 stamina, and +5 defense by vaulting items.
I've been looking this up for a will and by the look of things it's on the back of the engine some were around the exhaust manifold
it could have a bad air filter or the fuel is clogged some where. or the batt could be going bad.
You might take a look on Ebay Motors. There are usually some darned nice Sunfires (and other cars) listed for sale. FriPilot
If it is a 4 cylinder it has 4, V6 then it has 6. Some 4 cylinders do have 8 plugs, Ford for instance, but not the GM 4 cylinders.
Some early model Sunfires have a dipstick. In my '96, the dipstick is located near the firewall, down and inboard from the brake fluid reservoir.