Wont pass smog. Too lean '91 civic wagon
 

engine: d16 & intake is dual point fuel injection ---I went and swapped a d15 engine with a d16 engine and i placed the dual point back into it. Took it to get it a smog and the results was that it was running too lean. The service guy recommended i check the fuel system and or vacuum hoses for leaks. The vacuum hoses are placed properly but i can hear what seems to be little hissing noise near the throttle cable. i sprayed water with soap to see if i can see bubbling for air escaping and nothing. I have not checked the o2 sensor on the manifold just yet. The car doesnt idle too bad but its nearing 900 rpm. any advise on what directions on to check for first. could electrical issues be the problem? There are no engine codes. Much appreciated for any advice.

vacuum hose lines are checked with starter fluid, not soapy water. try the vacuum leak check again. if the idle increases, youll know youve got a leak.

cool il give that another go and check the idle