Hi, I recently swapped engines from a very bad D15B to a better D15B with about 80,000 miles and in great condition. The swap went well or at least i thought so; however, i need a muffler and to check the timing still(right because I pulled the distributor?). I removed the A/C compressor,condenser,and evaporator could that be why the check engine light is on since the swap last week or is that cause we went from an auto to manual transmission? The problem I'm having is that the the new Civic(exactly the same 1990 lx but 5 speed) won't stay running' when i start it on cold Wisconsin mornings. I've tried to find anything we missed(connector,vacuum,etc) only to remain stumped. I've recently found out the alternator is bad and I'm putting a new one in, but this cold start problem happens with a newer battery and with a charger on it the last two days on trickle. The engine tries to stay running but stalls unless I keep the rpm's up. After about one minute of holding the idle with the gas pedal, it finally stays running' but at a real low idle(like 500 rpm) Then, as long as it doesn't sit all day, the car runs fine but is very jerky @ certain rpm's in certain gears. The reason I'm stumped is because i never saw this problem when that exact 1.5 liter was in my original 1990 lx (automatic)just last week we swapped... why would this be? what about the Idle air control motor? I've never cleaned it or replaced it, but there was never a stalling issue before with this particular motor???this was my first engine swap, but i didn't go at it alone; i had the help of a skilled mechanic thats pretty good with Honda's. Any suggestions or Ideas would be great or if you all can think of anything i didn't. Thanks.