I have a 2004 Accord EX 4 cyl. I have just replaced the starter by removing the intake manifold removing the old starter and replacing it with the new. I was very careful to try to reconnect all of the vacuum lines and electrical connections and I'm pretty sure they are all correct. However, after starting the car the engine will idle around 1,000 RPM and then surge to 2,00 RPM and then back and forth between the two approximately every 5 seconds. I have noticed that there are two large cracks in the intake tube between the air filter and the throttle body but one on of those was there before I began and likely the other one was too. I have a replacement on order but for now I had placed duct tape over the cracks. After driving the car at highway speed for a few miles and then around town, a check engine light came on. Thinking the computer needed to be reset, I disconnected the battery for a few minutes and reconnected it. The light went out but the surging continued. The problem feels and acts like a vacuum leak but I have no way of knowing for sure. Any suggestions would be welcome.
Thank you

 

Try spraying a generous stream of water around suspect points in the intake system. Listen for a change in engine idle (stumble). You should be able to find an air leak.

good luck