help car running hot

i have a g2 with a 94 gsr swap. my car gets hot when it goes uphill almost to the h on gauge. also my car gets hot after about 15 min of highway driving and the gauge will go up but then in like 2 mins starts to go back down towards the middle between c and h and i want to know what is causeing this its driving me crazy

check your coolant

or termastat

coolent good its only when im on throttle or going up hill it get hot i have a 94 gsr swap and do u know if i have an egr valve on that motor the car is 5 speed

chnged thermostat no more problems the only problem i have my gas milege sucks like 150-160 on a 13.2 gallon tank i drive so slow to see if that helps and it doesnt

Did you change the fuel filter before that swap?

changed fuel filter twice in last 6 months still bad gas milege

o2 Sensor?

yea everthing is fine now knock sensor wasnt hooked up but everything is cool now like 30 mpg