i have a 1994 mustang coupe ......3.8 v6 ...the car has no power going up hill ,and sputter alot when i step on the gas. Ive changed the plugs,wires,air filter ,fuel filter ,cleaned the maf sensor,run fuel injection cleaner through it , but the car still does it ,,,,,,any ideas ??

 

Any chance you have a Mustang buddy with a 94-98 or even a 99-04 V6 Mustang you can ask to test out the ignition coil? When mine was bad, it was a "speedy" type of miss, or sputter. Felt horrible to drive it 10-20 feet down the road.
It really could be a number of things. I'm surprised there's no codes yet. Spark plugs sound suspicious, or the wires not placed correctly. But if you had this before tuning it up, maybe you should try somehow to verify for free thats its an ignition coil thats bad. I dont know what kind of relationship you may have with a parts supplier. I would like to think they would let me put one on really quick to see. I tried Ohming mine out but got consistent readings even though it was bad. If you have a choice when ever you do get one, I would suggest a Screamin Demon ign coil. A brand new Accel would not function on my car.
Also, if its a minor issue. Perform a Seafoam treatment right away. And do it the right way or don't spend the money. Suck it up through a straw into the pcv valve. Update please.

 

could have a clogged cat, im having a similar problem and i think that's my problem.

 

I was told that a smell was associated with that. Maybe even noises in there.

 

My 94 was sputtering about a year ago and it ended up being a blown head gasket. Is it running hot/overheating at all?

 

yeah definitely have a smell, and i think noises

 

This happens to me too sometimes...but its randomly. Sometimes when I turn my car on it doesn't start properly, it starts to sputter. I have to rev it to clear it then I can drive!

 

i had the transmission filter changed on my mustang and put all new fluid in it ......no more sputtering car is running beautiful .,.....