Sounds like you may have the dreaded but common speedo sensor failure, because the ECU is no longer getting accurate speed data it believes the car is stationary and drops power to the engine.
This can cause stalling and sluggish handling.
Sounds like your car stalled in slow time.
I recommend you get the sensor replaced or at least get the wiring to it checked as it can break causing an intermittent fault.
When the speedo dropped did you also notice if the tacho stopped counting up?, this would definitely point to the sensor.
The parts required are about £25 on eBay but changing the sensor can be a bit of a pain as it's on top of the gearbox housing and is a sod to remove as it fits in very tightly.
TBH though, the retaining pin is the hardest part as the original ones aren't too sturdy.
Speed Pulse Sensor failure. It's such a common fault So common i'm just about to change mine for the 3rd time as I'm having these issues too. Might be an idea to dump and refill the gearbox oil as the failure 9 out of 10 times is due to swarf contamination.
i would look for a fault in the power supply system...battery/connections/earth leads etc
Got some news for you (touch wood) its fixed!!
Yesterday, the mechanic came to look at it again after the power failure I told you about. Well, he put new spark plugs in it, new air filter and oil filter and he called me to say it was running great! He said he'd drop it off for me before work, but he never arrived.
I got a call from him saying that he got about a mile away from my house, doing about 45mph and it just completely died, all the usual things happened, power steering went, brakes failed etc. He said he caused a huge traffic jam because someone almost hit him as it kind of careered into the other lane. He managed to push it into a bus stop in the end. It wouldn't turn over at all. Nothing. Dead as a dodo. All it showed was an amber engine management light. They towed it back for diagnostics and it came back that the crankshaft sensor had failed!
You should have seen the state of that crankshaft sensor! it was snapped in the middle and had a broken tiny copper wire in it all shrivelled up! Looked a right state!
So, all the work is now done. Air filter, fuel filter, spark plugs and a crankshaft sensor. Drives like a brand new car! CRAZY
@Stoney, i'd give up mate, OP seems to be ignoring you. ;)
So most likely cause was just crank sensor?
ermmm....how would that explain two broken crank sensors then?
crank walk isnt unheard of on a focus, but didnt think it was common...if its that bad then a prybar can show up the excessive endfloat...
if it is excessive, then only option is a rebuild...might get away with careful spacing of crank sensor, but doubt it would run perfect with this get around cure...might be cheaper to source a small block or 2nd hand engine..ouch
i agree with stoney the vss is at fault also i would take it to ford yes the crank sensor may be getting mashed up but is it the correct one in the car they are all different lengths if the wrong one was fitted originally and the mech fitted the same as a replacement it will be mashed up never heard of it on ford that much except on really misused engines so i would have the car into a no offence better mechanic having had the mk1 im well aware of the issues and symptoms crank sensors do not cause the speedo to drop out thats the vss failing
What he said ;)
the problem with non ford mechanics is they know little about the cars they will change parts and keep charging money till they stumble on the fix ford will take a look at it and check the cam sensor is the correct part for the car then take a look at it plus they can plug it into the diagnostics toi see what happen s in real time
this is how I got my speed sensor out may help
artscot...sorry bud but that is rubbish
ford mechanics/dealers are no better or worse than any other...including charging for unecessary work, in fact my experience shows dealers are the worse for charging what hasnt even been done.
your all slating a mechanic from over the www, and even the info about the damaged crank sensor wont change your mind...
trust me, diagnostics isnt an exact science, i have had plenty of experience of symptoms that absolutley scream at a certain part being at fault, only to find out by proper diagnosing that fault lies elsewhere. this is why i try and encourage testing first, ahead of just renewing throughout my involvement on this site.
from an early post, if info was correct, i noticed the point about the radio cutting out, speed sensor wont do this, it can change the volume but it wont cut it off, thats why i earlier suggested its a power supply problem, a collapsed crank sensor can affect speedo and rev counter, have seen it happen myself, it can also cause a power failure.
it may very well turn out to be a combination of problems in the end, perhaps a failing vss thats now been overshadowed by the crank problem...either way, its not fair to slate a mechainic purely on the evidence supplied, and complete rubbish to suggest ford mechanics will know and deal with it better than anyone....they have good mechanics dotted about, as does a hell of a lot of so called back street garages and sole traders...
rant over...apologies, just gets my goat when its suggested dealer mechanics know far more than non dealer
and breathe :D