Thank you all for your replies and thank you for the link. I had no idea what some of those sensors were. I will start testing them. Then I have one more question, does this 90 cherokee need all of these sensors to function or can they be bypassed. If so were can I find that info. out at. I live in a state the does not have emission inspections. I know alot of them are for emission, so are they necessary? I will keep everyone posted on my progress. Thanks again