Pitbull69

Been noticing more and more my car at low revs is jerky, and can stall occasionally too,

Today I watched the rev counter and to me it looks like a problem, could anyone tell me what I should be checking.



car has had new plugs, Magnecor HT leads, and an oil change recently, its also had a new air shut off control last year, (I keep seeing these can be a problem, but is a year really all they can last ? )

thanks in advance

Sniffle

iTrader: (1)

Does it hang at 2k rpm if so it could be the IMRC - P1518 fault code

Could also be a faulty coil pack
seeing as you changed plugs and leads are they getting any flash over
would be due the the leads not seating properly
the ceramic would show some signs.



To be honest I'm not at all sure, Mine does the very same thing but it comes and go's so I can never find why
Same as you new plugs, Magnecor set.

Glenn_

iTrader: (1)

Lambda sensors could cause this too. I would try and get the fault codes read.

Has your mpg got worse.

Pitbull69

Thanks guys, never had decent MPG tbh, around 200 Miles from a tank, I used a code reader before I remapped my car and it showed no faults, but I will plug the bluefin in and see if that shows any codes.

According to the paper work I got with the car lambda sensors was changed too, I have got a very sooty exhaust, MOT tester was surprised i passed the MOT.

Pitbull69

Both diagnostic machines I used have come back with 0 errors, does the fault always show or can the fault sometimes be there without a code ?

I have also noticed the top earth wire looks a little damaged, so its not making full contact, will replace that over the weekend, but not sure if that would cause my revs to do what they are doing

stevo123

200 miles per tank is quite worrying, that's about 17mpg! Gotta be something wrong somewhere.

Were the new plugs gapped?
Have you had any water on the engine that might be sitting in the plug wells?
Was the fault there before the new plugs? (new plugs can be faulty sometimes)
Is your fuel pump making any unusual noises?

Sorry I can't be of more help, not had a lot of experience with the ST. Good luck fixing it though.

Sniffle

iTrader: (1)

lambda's can be a bit tricky as they don't always throw out a fault code or they are totally fine and give a code, My EML used to come on for them in traffic but would go on next start up

lambda's read the exhaust gases and adjust the fuelling to run the engine correctly
so if the sensor plays up it can mess about with what the ECU is telling the engine to do.

Pitbull69

I never gapped the plugs, I presumed they came pre gapped, and they looked the same as the old plugs that came out. I will check the gaps on the weekend too.

Not sure if the car being jerky was there before the plug change, but the MPG was just as bad, I have ran 2 bottles of redex through the car,

No water was there when I changed the plugs before, but will have another look when I check the plugs,

I thought fuel pump this morning so checked when I turned ignition on, and it sounds normal, so dont think there is anything untoward there,

Its going in the garage tomorrow to get coolant changed and fuel filter changed too.

So is there anyway to check the lambda sensor apart from trying a new one ?

RichieST

iTrader: (2)

Put some genuine Ford plugs and some genuine Ford leads in. I've seen a fair few Zetecs now with ignition problems caused by aftermarket plugs / leads.

Pitbull69

Plugs are genuine ford plugs, that was the reason I changed them as it was running Bosch Super 4 and I had read on here that after market plugs wasn't much good for my car, but Also changed the leads on the advise that the ford ones was quite a weak point and a good alternative was the magnecors,

I can always swap them back over the weekend, only takes a minute so worth a try either way

Pitbull69

Just back from the garage, and he said the IMRC is working as it should, he said something about the lever moving when it should,

Im sure I have read before that if the IMRC is working it could be the manifold at fault, is this right or my imagination ?

He also said some cars deliberately hold the revs for emissions, but wasn't sure if the focus was a car that did it,