Audi misfiring and spluttering - what's the cause?

This morning I pulled up on the grass outside my house to take something heavy out the car, when pulling off I accidently drove over a concrete stump which pulled out the ground and dragged under the car, snapping the radiator bracket, the power steering sensor/plug and cracking the radiator so bad that it wouldn't hold any water at all. There was already a slow leak of water from the radiator so at the time I didn't notice the damage until I put water in later. Just after noticing the damage the car started spluttering while on my way to get the parts to repair everything. So, I've replaced all the damaged parts. New radiator, pipes and power steering sensor. Picked them all up at a breakers yard for £25. Unfortunately, the car still splutters. The damage didn't crack the sump and there is no oil leak, so that can't be the issue. Obviously I drove the car another 2 miles after it started spluttering, do you think this could cause the issue? Also what is the likelihood of it being the coil pack? I don't want to buy any more parts if it's the head gasket (though there is no white cream coming from the oil cap) as if it is the gasket I would be better off just buying an engine from the breakers for £120 and dropping another lump in it...
When you say spluttering, is it misiring and if so is it through the engine range. Does it miss fire on tick over?

Have you checked all air/vacuum pipes/connections for any leaks? And have you tried removing one plug lead at a time to see if there is a noticeable change to the engine?

You appear to be quite efficient with dealing with your car, so it may be best to carry out a compression test on the engine, as this will confirm if the head gasket has gone or not.
Answered by Alan Ross on

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