Expert: Sean Halliday - 4/6/2009

Question
I purchased a used 1993 honda civic that has a rebuilt engine and seemed
like a good deal at $1000.  However, the check engine light is on with code
14, iac valve, and the car idles very rough when it is cold, and the car
stumbles when it is driven even after it warms up.  I replaced the iac valve but
continue to get the same error code even after clearing it out.  I think that I
may have a vacuum leak, since when I put my hand over the throttle body it
does not die, but idles way down.  The previous owner replaced the tps
switch, and took off the throttle body recently.  My question is, where do you
think the vacuum leak is coming from?  I have very little money so it would
really help me if you could help me solve this issue.  Thanks.

Answer
The sure way to tell for vacuum leak is use a gauge.If there is a leak at the throttle body,replace the gasket and check all hoses.To say for sure is impossible where the leak is as i would need to see the car.You must check all possible places for leaks.Spray some soapy water around the suspect leaks and see if the idle changes.That will tell you if there is a leak.If the previous owner removed the tps,its possibly set wrong.