The car feels like it is running strong, but my mileage has gone to the toilet. It went south after I added sea foam. Since then I have gotten about 56 miles on the average less per tank with no additional mods.

My NGK plugs and MSD wires are 3 months old, I use a G2 CAI, BMR STB, Cutout, SLP IAC, Jet Air Foil, No MAF Screen, Ported MAF,

 

You may look into changing your O2s and plugs. All of that crap coming out of your engine can cause them to get really dirty.

 

When I used Seafoam it knocked both of my O2's out--so this may be something you want to look at.

 

on high mileage O2's you will kill it with seafoam. Change them out (they're expensive) and you'll get your gas mileage back. Its definitely worth it and ifyou keep it up they won't go out again.

 

I've never had any problems using Seafoam. Maybe there is some other reason for your mileage drop.

 

Now it said you can put it in the gas tank.. So I did... It runs strong, no hesitation, no change in idle, no upper rpm miss just a major loss in mileage. Was thinkinig of 02 sims for the rear..

 

would it be ok to pull the o2 sensors when using it, then put em back in once all the carbon and stuff is out?

 

yep...most people suggest that to be safe. But once you've seafoamed once, that much build up shouldn't happen again if you do it regularly (every oil change or so) so you O2's should be OK after that.