Bad sputtering problem!
 

My mom has a 94 grand marquis. Ok when its cold its the worst. you have to let it warm up for ten min before you can drive it or else there is no power and sputters very bad. Even when its warm it still occurs but its drivable. The CEL used to come on and off every now and again and we could never catch it to come on when we had a scanner hooked up. We recently put a fuel filter on and now the CEL never comes on! But the problem still exist the same. Makes no sense to me. If it was the TPS wouldnt it throw a code? what could cause this problem and not throw a code at all?

Did you ever get it figured out? Im trying to help a friend figure out the same issue and we are not getting very far.

New Plugs, wire, O2's, gutted Cats, new fuel filter, New tranny (not that it matters)