OK First couple of things...
What year is your Zetec?
Cold Air Intake (CAI) or just replaced the filter?
Removed the air box or just partial?
Did you reset the computer?
How long has it been doing this?
Gas:
Did you go to a new location to get gas?
OK so there are a few things to look at when making this kind of mod. Number one, reset the computer. This ensures that the computer resets the way it does your mixtures. Number two, once you do that, it is a known fact that the computer will spend some time "relearning" what was "deleted" when you reset the computer or when you made a change. Third, CAI, yes yes yes! Check all your clamps and ensure that they are tight. Check to see that you are not blocking or restricting air flow in. A leak can really cause havoc! Trust me, I know. I started building my CAI and the first time I had it attached to the throttle body, I tested it on the road, and the intake tube at the elbow into to the TB came out. Talk about a LOSS of power and having to LIMP it home....NOOOO FUN......So check all the clamps.
Gas can cause major probs as well. I stopped using 89 and I now use 93 always. Some people say it doesn't make a difference, but I have found that it does seem to run smoother and is a little snappier.
Other things to consider. Remove all the resonators on the intake. The 96's had a "paddle" resonator before the TB and after the IAT sensor AND a resonator in the fender.
I have removed both of those AND the plenum piece that goes over the TB and replaced it with a rubber elbow.
LOVE IT
L8R
Rich
