Ford Fiesta Hesitation

[MBleM]

My 1996 Ford Fiesta is starting to become a pain in the ass. Before it didn't had much power especially to climb hills and it use to burn alot of gas. i then replace the coil pack with a used coil pack from off of another fiesta i have (its not running i bought it just for parts). It solve that problem but after driving it for a hour it drastically lost power going up a hill as if to shut down but when i eased my foot off the pedal it recovered (it never did that with the previous coil pack). ever since that i've been experiencing this problem over and over. if my foot is steady on the throttle it works fine but wen i put my foot down it cuts back until i ease my foot off the pedal. one time i decided not to ease my foot off the pedal just to see what would happen. it decelerated all the way down to about 3mph at about 1000rpm then it just instantly accelerated with astonishing speed then the process repeated itself (the pedal was floored throughout the entire trial). i have a gut feeling its the coil pack but jus wanna be sure. i would appreciate all your help and advice on this one . thanks

[TWR]

When you replaced the pack did you clean the contacts? Did the fit correctly over the plugs? Did you replace the plugs or checked them ? when was the car last serviced? a lot of question but the answer will be there>

[MBleM]

I've just recently serviced the car. plus the contacts fit correct and they were clean on my recent inspection. i also realise that this problem would only occur wen the fuel level pass half ( but i've jus install a new fuel pump about 4mths ago). I took the tank down check the pump and clean the tank still the same.

[TWR]

Without looking it seems you have a fuel flow problem MBleM, what made you change the Pump? was it to do with your initial problem? I once had a fuel line problem with a VW beetle, It turned out someone had used a thick self made Rubber Gasket within the tank where sender fit & a piece had dropped in the tank & was getting picked up and blocking the fuel line.

[MBleM]

The pump was ceased cuz the car was stationary for about 7yrs (i bought it from a dealer so i had to replace it to get the car working). But last nite i was trying to see if there was any other problem and i realise thAT my spark plug leads are leaking. first it appeared faint (only 1&4 was leaking) but it gradually increase till i can see the current flowing from all the leads. I now know what the problem could be for the hesitation but what have me puzzled is y would it only hesitate wen the tank past half. thanks for your help

[TWR]

I presume you replaced the lead FULLY? I can only assume there is water within your tank with standing for that length of time, as you know water rises & will be drawn through first, with respect If I would have bought the motor knowing the length of time it has stood the first job would have been is to drop the tank, Fuel Filter, then the line up to the Carb, When you replaced the Plugs were the Electrodes Clean/ brown? was there any oiled up, If the latter Valves/Piston, get each Cylinder compression tested.