hi, i have a 98 civic ex coupe, i am at 138k and just did a major service from honda. Its like - 8 degrees outside, i left my car outside for like one and a half day, and i had my block heater plug in. For some reason, the engine takes like 15-20 seconds before it actually starts, and also once its started, the engine seems want to die then slow rev up.

when it was started the rpm was at around 1200 then it slowing rev up.

the sound was like misfiring, it started half way but i had to hold the ignition till it starts completely.

does anyone know what is the problem? is it my battery? engine timing? ignition(was tuned from honda 1 week ago)? map sensor?

thx