Engine running cold and bad gas mileage
 

Another thing Ive noticed with my 93 Z28 is that the car doesnt seem to ever go over 150-160 degrees. Idle, city driving, highway driving.. its all the same after the car gets warmed up. Ive done some research and I should definitely be over that by what.. 30, 40, 50 degrees? I dropped 20 bucks in her once I got her registered and ran about 80 miles. With gas being 2.40 or so, I did the math and it averaged out to about 10 mpg. My first instinct was that the thermostat was stuck open, completely removed, or a previous owner put a 160 degree thermostat in it.. but I havent had a chance to check yet. Im going to check in the morning once I get home from work(nightshift).

Would running at 150-160 degrees on a (presumably)stock LT1 really cause my gas mileage to take that big of a drop? Or do you guys think there might be something else at play?

I also noticed in the fuse box that the fuse controlling the fan which is supposed to be a 10 watt fuse.. is actually a 30 watt fuse. Can the fan affect temperature that much? When I brought the car over for my dad to see.. we noticed that fuse and he was like, "Go turn it on." So I did, and let it idle for a few minutes. He had the fan fuse in his hands when I turned it on. About 3-5 minutes into the car running at idle, he put the fuse back in place and the fan turned on. Then he removed it and obviously it turned off.. but should the fan have been running there at idle like that? I thought they didnt engage until the car got up to temp because engines are more efficient at higher temperatures.. or am I mistaken?

Thanks yall. :)

flash for trouble codes. look at 23 here 4th Gen LT1 F-Body Tech Aids also look at 12 while your there

What was the temp when he stuck the fuse back into the slot? 93 has one fan kick on at full speed and if need be the second will kick on at full speed. Fans shouldn't kick on till 226 degrees

Ok i just flashed the codes. Im getting 26, 32, 61, and 64.

26 - Evaporative emissions canister purge solenoid circuit

32 - EGR recirculation

61 - A/C system performance

64 - Bank 2 (right) O2 sensor, lean

Ok so Im reading the service manual entries on these.. 26 seems a little over my head, but 32 I can sort of wrap my head around. It says on 32, DTC 32 can be caused by a leaking exhaust system and any time Ive had the hood open I can smell exhaust. Looks like 61 relates to my other thread and based on the last response from a guy, I might be able to fix that one myself. After reading 64.. it almost seems like maybe 26,32, and 64 are all related perhaps by some exhaust leak? Im just guessing here and could be wrong but based on the service manual articles.. it seems like theres some corrolation between these.

exhaust leak can cause 02 sensor to give false readings. 02 sensor may be fouled. evap can cause lean or rich condition. test gas cap, look over evap hose/pipe for leaks. ac fail can cause fan to come on all the time. i would say three issues.

26 is an electrical failure. Check the EVAP solenoid and it's connector. Not related to the others unless it is stuck on.

Hmm alright well thanks so much for the explanations guys. Ive put gas in it a few times now and regardless of the level of fuel in the tank.. It seems like alot of pressure is built up that when I remove the gas cap I get a loud "whoosh" (lol best I can explain it). I'm definitely going to fix what I can and I'll get back and let you know what I find. You guys are f****** awesome :D