92 duster stumble

[89daytonashelby]

hey all, my grandma has a 92 or 93 duster that me and my dad took the V6 out and put a 2.5 N/A in it. It has been running great for a couple years but all of a sudden it started acting up...when she is driving down the road it will cut out, it keeps running and as soon as she floors itit kicks down into lower gear and goes again no problem. We did a tune up and that didnt do much...so what could it be????

[NAJ]

You stated that it " Cuts Out but keeps Running" Can you Clarify?
Any Particular Speeds? On Decel, while Cruising at Steady Throttle? Does the Engine Completly Stop Running,Does it Stumble, Sag, Hesitate, Surge?
Does the Check Engine Lamp Illuminate?

[89daytonashelby]

Ok, i havent driven it so i am going off of what she is saying. I think it mostly does it when she is driving down the freeway. It will just loose power and start slowing down until she floors it and it kicks down into lower gear and then it goes fine again. The engine light doesnt come on and it keeps running.

[NAJ]

When will you be able to drive the vehicle to verify the complaint and post any other syptoms that occur either while the problem is occuring or when she accelerates such as Popping/Backfire,Smoke or if any Faults were set.
Off the top of my head things such as Fuel Pressure,Restricted Exhaust could cause the vehicle to Lose Power but would not correct themselves when accelerating and then be gone.

[89daytonashelby]

within the next couple days i will get up there to where its at and drive it