Hi i have a 03 fiesta lent it to a mate long story short he run it with low coolant blow my heater pipe spark plugs and the rocket gasket if i got that right and now all I get when flooring it is a judder engine light comes on as well as temp light stops when i ease of revs up upload my vid 

Here is the vid sorry i didnt realise radio was on and not the best vid but hope it helps 

 

They was oil under the rocket in the spark plug wells has that cleaned new spark plugs ht leads and a new coil pack and a rocker gasket done and still same 

I would suggest that if he has run it with low coolant then possible damage to cylinder head & gasket. I had a Peugeot 206 that would judder when floored, found out it was down to a blown head gasket - Note head gasket and rocker gasket are 2 different things.

If the head gasket has gone because of high temp, you'll have warp somewhere. You'll need the head skimmed at a machine shop

I had aa out and they tested it and said all was fine I dont know how they didnt pick it up 

Iv tested the alternater as we'd told it could be that all's fine im lost now do t know where to go from here

1 hour ago, bigbob87 said:

Iv tested the alternater as we'd told it could be that

From the vid it does look like an electrical problem of some sort. Especially with the battery / ignition light coming on & off like that.

Bad earths, battery connections, intermittent alternator fault, through to electronic or CAN bus faults, it could be a lot of things.

If it is not losing coolant, then the head is probably ok. I can not see that fault being a mechanical problem in the engine.

But thinking a bit more, faulty coil pack is possible. Or even coil leads (if fitted). If it was arcing over inside, that could upset the electronics to make the lights come on. It would cause judder. It is most likely to happen at wider throttle openings as the higher cylinder pressure needs higher voltage to spark.