The problem started after replacing the spark plugs (new NGK EOM).

When accelerating right after a cold start, the engine seems to misfire for the first 30 secs. Once the engine heats up, it is smooth. The problem is not seen, if I warm up the car first.

Any ideas what it could be? Could it be the plug gaps? I am thinking of re-checking and adjusting...

 

 

96' Legacy Wagon 2.2L

I had a Toyota do this once, caused by a faulty plug wire. When the conductor warmed up, it grew just long enough to get the spark to jump over the open spot.

 

Maybe when you pulled the wires off to change the plugs, one of the cables was damaged...

I replaced the wires with new ones when I changed the plugs. But one of them does not snap in to the plug with a popping sound no matter how much I push. It appears to be tight. You may be right that this wire could be the cause. I'll try again to see if I can get it to seat properly. Thanks.