n reg mondeo misfiring - lboardman32
when i start up my mondeo it misfires but starts working better as i drive more. i have recently changed dizzy, plugs and leads but it is still misfiring.
what else could it be?
n reg mondeo misfiring - ChicksFan
I guess the 1.8 engine you have is similar to that which was in my daughter's 16v Escort which had similar symptoms to your car. Baffled me entirely but our local garage found that a core plug was beginning to fail in the cylinder head with the result that one of the spark plugs was receiving a very fine water mist spray with the engine running. Of course, with the engine switched off while I was looking for the problem the water mist wasn't there. My garage said I'd have never have found it on my own.
Good luck with sorting out your car.
n reg mondeo misfiring - percy
Perhaps a bit unlikely considering age of motor, but are you using 5W/30 oil to save the tappets hydraulicking? (Is that a word?) Also if you haven't already done so drop the plug gaps to 1mm, to save the coil pack and leads from being overstressed. Good luck!
n reg mondeo misfiring - ChicksFan
Hi Percy,

I don't disagree with the other possibilities you suggest but - age of the motor? It is 11 years old.

Anyway, best of luck boardmanl32, let us know how you get on, and what the solution turns out to be. At least you've got some points to consider.

n reg mondeo misfiring - Hamsafar
Somebody at work has one same age/engine, low compression on 1 cylinder has been diagnosed which when the engine is cold has more effect, but the cause has not yet been discovered, but sounds terminal. Can you uplug HT leads one by one to isolate the cylinder? Be careful not to get a shock, if you aren't used to doing this it would be wrong of me to recommend doing it.
n reg mondeo misfiring - bell boy
if you read percy"s post he says that the oil should be 5/30 if this is not used then the hydraulic tappets with thick cold oil in until it warms and thins will give misfires first thing and also give a low compression reading on any cylinder due to a valve not being able to shut
n reg mondeo misfiring - piston power
does the misfire happen from cold or when been stood for a few hours or more?? if so maybe weeping head gasket into cylinders causing misfire then clears after a 20 secs, you could remove the plugs see if any brown?
n reg mondeo misfiring - lboardman32
Thanks for all advice. I have changed leads, dizzy, and oil. I realise that it will take a few days for oil to work through properley. I checked the plugs and they are perfectly clean nothing on them. The car is still misfiring. When i start from cold it won't pull away at first. It's like there is no power. When it does pull away it starts driving normally for a while but then it starts jerking and then seems to drop power again and i have to drop it into third gear.

Thanks for all help.
n reg mondeo misfiring - Screwloose

Does the reference to having changed the dizzy mean that you have changed the coilpack? Has it had a new cat fitted recently?
n reg mondeo misfiring - lboardman32
yes, have changed the coil pack, but not the cat.
n reg mondeo misfiring - Screwloose

Try disconnecting in turn, the MAF sensor, [next to the air filter box] the temp sensor, [square 2-wire plug on the back of the head] and the exhaust gas pressure sensor [black, rubber-mounted thing in the middle of the bulkhead and see if any of them makes a difference.

Doing that will set fault-codes in the ECU, so if you're going to get it read - the best idea, frankly - maybe get that done first.
ford mondeo misfiring - lboardman32
I've decided to try again as i got some good answers earlier in the month. I tried them but nothing yet. My N reg ford mondeo is misfiring badly. On start up it misfires for about two minutes, if I try to raise the revs it makes it worse.While I am driving any speed up to 60 miles an hour it misfires intermittently and drops power. Any ideas please. I've tried changing the leads, plugs, coil pack, checked vacuum leads, throttle body gasket. I've been told it could be the ecu. Can anyone suggest anything I'm desperate.
ford mondeo misfiring - Number_Cruncher
what grade of oil do you use?

ford mondeo misfiring - lboardman32
5/30 oil
ford mondeo misfiring - Number_Cruncher
Yes, I've just gone back and re-read the earlier thread, where you say that you've changed the oil.

Perhaps it might be better for a helpful moderator to tag your new question on the end of your old thread, to avoid people telling you the same thing over andover again? {Done - DD}

mondeo misfire - lboardman32
i said about my mondeo misfiring etc earlier on. i've just been under the car and noticed that the catalytic converter is leaking. could this have anything to do with the problems i've been having?
mondeo misfire - Dynamic Dave
Could well be.

Any air that enters the exhaust system upstream can cause unburnt fuel to ignite.
mondeo misfire - DP
Have a feel under the coil for a rubber T-piece that joins three pieces of vacuum pipe together. My dad had this split and it caused all manner of weird misfiring and idling problems.

It's free to check anyway, and if needs replacing, it's about four quid from a Ford dealer.

Did a temporary repair on it with a puncture repair patch and some vulcanising solution which held for the two days it took for the local dealer to get one in stock.


Ask Honest John

Value my car