The transplanted 2.2 in my 98 OBW will make a single back fire when engine firsts start from crank of the starting motor. This seems new. Is this something to be concerned about?? Engine runs fine, no CELs. Just seems strange. Got me concerned.

Backfires through the intake? Does it do that every time you start it?

Backfires through the intake? Does it do that every time you start it?

Yes, just a single "pop" when starting the car.

I would check the timing belt and make sure it hasn't jumped timing.

 

This could also be caused by a leaking fuel injector or o-ring. Or you could have a valve that isn't seating all the way.

yea, wondered if maybe a valve problem.