I have a 1991 z28 with a 305tpi. 3 years ago, I had a performance shop built me a 305tpi roller motor. I had them rebuild the engine +.030 with 10.1 compression. I Port matched the original heads and TPI intake to the gaskets, installed a Lunanti hyd. roller cam with .512"lift, a JET chip, Hooker headers, complete Dynomax exhaust with 3" pipes and single outlet muffler. I replaced the original 2.73 gear set with a 3.42 and had the transmission rebuilt with a shift improver kit. Well a month ago, I put it up forsale and it started to act up. It was showing signs of a blown intake manifold gasket. Replaced it, still wasn't fixed. Took it back apart to find out it had a broken piston. It was never showing signs of it until I pulled it into the garage to pull the motor. I replaced the 305 with a 350. Completely overhauled the 350 with new bearings, cam, lifters, timing chain, etc. I got it all together and broke in the new cam but in the meantime fans never kicked on. It has a 180 Thermostat. I checked the Fuse and it was fine. Replace the temp sensor still nothing. Well I left the hood off and took it around the block. Car ran Grat and strong. Temp stayed down due to no hood and air getting to it on a cool night. Well I drove it into work today and it ran great. Went out to lunch and started it up and ran ok for a few min and then started to run rough. Well I went in and ate lunch and went back out an hour later. Start it up and it is running like a total pig. It's like 2 wires are cross or not plugged in all the way but everything is correct. My question is, could it be the computer? Should I replace the computer and put in a different chip? Also, what else could be causing the fans not to kick on? Any feedback would be helpful. Thanks!