My mechanic thinks that my car isnt running right bc the ecu is providing a poor mixture when cold starting, he think s the port and polish has something to do with it...has anyon experienced anything like that? thanks -John
P.S>its a 97 1.8t QM

I had a pretty aggressively ported 7A, and had zero starting problems.

can cause problems like that.

all of my intake runners have 3 individual runners i guess you can say, about half a finger deep each...they all run to each intake valve...just make a 3 with your hand, thats pretty much what they look like, coming from the valves out..ie your hand is the head, and the tips of your fingers are where the intake manifold meets the head...

The person performing the P&P "needs to know" where & how much material to remove, or add.

This does not alway make a head flow better, or increase the swirl inside the combustion chamber.

Make factors involved. Main reason those who P&P, "know" where & how to make gains from particular heads.

All the ports need to be identical.

If those valves are not seating correctly, etc, or if you're experiencing overlap or anything from changes... problems.