I have a 91 Camaro RS, with a 305 TBI. My question, when ever it is a bit hot out, the tempreture slowly creeps up. I removed the thermostat, but then it wouldnt warm up very fast so I replaced the thermostat with a 160 degree hi-flow. Helped a little, but it still happens. On mild days, its pretty good about staying cool. And I flushed the system twice.

Any advice would be awesome.

 

Do you have the air deflector on, and is there a ton of leaves and junk between the radiator and a/c condensor?

 

If you leave the cap off and let it warm up, eventually can you see the coolant flowing? Can you see any growth inside of the radiator?

 

I have a few leaves, but not in the way of any air flow. My air deflecters on, i brush it all the time. lol.
And the radiator flows, and as far as i know the fan works. when i kick the heat on it will usually bring it down, but it gets old having the heat on in the summer.