I just did an engine swap on my 95 civic, from a d15b7 to a d16y4. Ever since it was put in, the d16 has had some running issues. It has trouble staying on when you first start it up unless you rev it a bit. It also has lots of trouble starting if there's around a quarter or less of fuel in the tank, but then will start first go if you tap the fuel relay. Once the engine heats up, it also has issues with steady acceleration. It surges a fair bit, and doesn't like being in 5th at all. I'm pretty sure there's no vacuum leaks. The only other thing I can think is injector O rings, they're hard to get for the car though so I'm looking for other options first.

Thanks!

 

Idles too low -- check / clean IACV. Make sure the coil has continuity (about 16 ohms). You may also need to open the air bleed screw on the top of the throttle body. Do not adjust the screw that stops the throttle lever.

Won't start unless you tap the main relay-- resolder relay. A very common problem. Slightly delayed starting when the gas tank is almost empty is normal. It's like you would have to crank for 2 or 3 seconds rather than starting immediately.

Misfiring under heavy throttle and low rpms-- weak sparks.