Flat spot acceleration

The pump needs setting up and timing adjusted.
If you fitted other than Ford injectors, that will also give issues of over fueling.

go to the magicmechanic website and send him this--hes the best there is and will rply

that should give you codes on computer, but look at ignition system cap ,rotor,plugs, wires, fuel filter

Can you describe what you mean by "flat spot"? Do you mean that there is par of the rev range where there seems to be little power? Turbo engines tend to produce bursts of power when the turbo spools up. Does the "flat spot" happen at low revs? If so, your turbo isn't spooled up yet. As you accelerate and it fires up you feel a rush of power. just a guess, provide more details and we'll try to help

replace the gas filter sometime when you let your gas run low it clogs the gas filter

Thats happen to me twice and the battery was bad

The fuel injector nozzle is partially blocked.Add fuel additive to clean the injector nozzle

It is possibly the O2 sensor. I had some issues with early 90's 4.0 liters where the O2 sensor would stick rich under heavy acceleration and would cause it to lean out and bog down. It felt like a rochester four barrel flat spot on an old chevy. I hope this helps.

Just taking a shot here as I have seen the same thing in the shop in that last month....I am going to throw you two scenarios as you don't say if it has a carb or F.I.
If it is Fuel Injection the filter or a weak pump would be the culprit.
If it is a carb engine there is an item called an accelerator pump. this pump pumps fuel into the throat unmixed so during startup and on acceleration it needs this raw fuel, on startup to just get fuel into the chambers and on acceleration when switching from the Idle to the venturi there is a dead spot that this pump covers for.. A 20 dollar rebuild kit for the carb is all you need. there should be a tag on the carb for the ID to give to the parts store..

had same problem,changed air flow meter sensor and problem gone.