I have a misfire that's very noticeable and no DTC . The coil, plugs and wires have previously been replaced and spark to each cyl. looks good. Fuel filter has been changed. I haven't checked fuel press. or vacuum yet. It idles smooth. When you snap the throttle fast, it sounds like it sucks air from the vicinity of the intake manifold somewhere. (EGR valve)? Doesn't sound normal to me. It has 113K miles. What really has me stumped is no code. With so many controlled components and no code, I really don't know where to look. I have an Actron reader that shows everything is good also. Any tips to point me in the right direction would be greatly appreciated.

Check maf i had issues no code. Had a used one from a escort 2 ltr put it on and all problems went away.

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2000 XLT single cab flare side
massive 2.5 ltr , 5spd
Bone stock for now except rims
mods done: OHC, instrument cluster and custom roll n lock bed cover.