So i have a 91 camaro with a 305 tbi. It was sitting about 2 years while i sourced a new 700r4. When i first ran it it ran and drove fine. It sat for another couple months and then it ran like a dog. Pushing the gas made it near stall. I swapped the computer and put the stock chip back in and it ran perfect for about a week now it idles very high shifts into first about throws my head back. Because of this it is also over heating at red lights. Also when i go wot it is hesitating horribly and dropping back and forth between 3rd and 4th I've check for vaccume leaks from what i could see by spraying wd40 near vaccume connections to see if it sucks it in. I'm not really sure what to check next. I checked the iacv and it seems fine as well. Any suggestions would be helpful. Thank you.

 

It sounds like you have multiple issues. If you are overheating, you might have a bad fan switch. Is the fan coming on? Your IAC, and TPS may need to be replaced. Check to make sure your ECM isn't installed properly. The "it ran perfect for a week" leads me to think you might have ECM issues.