ka24de HELP

[Scinto1]

hey everyone I'm new here and i need help . i recently bought a 1990 240 which the previous owner had begun a ka24de swap . It ran when i bought it but barely. i replaced plugs and wires with ngk,replaced fuel filter,replaced belts ,replaced the ecm(was running on single cam ecm) ,replaced the air intake due to it having a lot of vacuum leaks . now it runs better but it is misfiring a little and it will idle without the maf plugged in but when i plug the mac in it chokes itself and dies . if i give it gas it will stay on but to idle it will stall. now I'm assuming that the mac is bad but if there is any other help you guys can give me to help with this slow project i would appreciate it . also my tachometer doesn't work at all. (i thought the new ecm would fix that) i also bought a new lcv valve but i can't find it on the motor so if i can get a link to a video that shows or an image that would be appreciated . thank you for your help in advanced.

[KAT-PWR]

Try a new maf first, do a boost leak test.
Take a 2.75in pvc pipe end cap and thread a compressor fitting into it. Connect to a compressor and fill with air. Use soapy water to check for leaks.
Common areas are the tube that connects pre-throttle body to IACV/AAC and their associated clamps
Fuel injector rail grommets
EGR (if deleted)
PCV tree under the upper intake manifold

The IACV is located on the rear of the lower intake plenum it is held in by 4 bolts and has a large phillips head screw that faces toward the passeger side of the car
http://i3.photobucket.com/albums/y56/codyscool/IMG_3437.jpg

That will elimate vac leaks as a cause of idle issues and potential misfires.

[Scinto1]

thank you , ill do that now. i appreciate your help!