I have a 92 civic lx,when I first start the car the rpm's are at 800 then after a few seconds they even out at 1,000,but if I turn the car off after it warms up and try to start it again right away it stalls.Any ideas what would cause this?I just changed the ECU to a p28 from a p06 because the previous owner put in a d16z6 engine in.I have a cel on,changed oxygen sensor and is still on.

 

What is the CEL code? Is the oxygen sensor matched correctly with the engine wire harness? Is the latter matched with the ECU?

 

oxygen sensor was an oem replacement.I don't have a scanner to check the cel codes,i might bring it to my mechanic tomorrow morning for a scan.

 

You can pull the code(s) yourself:

http://www.honda-tech.com/zerothread/1901557

Afterwards, note the code(s) and clear the ECU. Run the car to see if the CEL turns ON and, if so, retrieve the code(s) again. Only codes that repeat are worth troubleshooting for repair.