Mis-fire but it cleared ?

[Rushy Racer]

A strange thing happened on the M4 today, my ZT-T 190 (45k miles) "appeared" to drop a cylinder and misfired between 3200 & 4000 revs for quite a few miles before I decided to stop at the services to see if either a) it would clear or b) the engine would not re start. Fortunately it was a). Any ideas ? BTW the tank was 3/4 full :confused:

[David3807]

It will probably have logged an error code in the ECU.

If it doesnt happen again (so that you have to fix something) remember to ask dealer at the next service what error codes were stored in the computer before he resets it.

[rdholmes]

I had something similar a while back. Same symptons. I have a 751.8T and I thought the turbo had gone or something !!

1) I changed the plugs and leads
2) I changed the coil on a "black looking" plug

All ok but then it came back a while (5 weeks ) later I decided to go "professional".

Went to the Rover garage and they said

1) the leads were arc'ing as they were wrong type (dont believe it as my son is a mechanic and got the right ones)
2) the STEPPER needed adjusting as it was well out (????)

Raised a thread on here (or the other forum prior to here) as I'd never heard of a stepper and people said that there is a stepper motor and if adjusted it might have cured things.

That was about 12 weeks back and it's been good as gold since. I'd guess it it is the same, and it does sound very similar, then I'd ask the Rover specialist to check if the stepper motor needs adjustment.
Hope this helps.

[Rushy Racer]

Thanks Roy, called in my garage this morning and I am going back on Monday early morning to try the test book approach and see if anything shows up.
I have had the symptoms a couple of times before, say when you drop a gear and floor it to try and overtake a vehicle only to have to lift off and abort the move. The " misfire" has then occured for a mile or so and then cleared as if one cylinder had been force fed too much fuel and choked itself !! But as I say thats only been a couple of times in 45k miles !!

[Rushy Racer]

Well, just got back from the garage and they say that it indicates that the inlet manifold is at fault, expecting a quote from them in a couple of hours, so is this it, has the deadly "VIS valve virus" final struck me down.
What price can I expect ??

[rdholmes]

Not that I don't believe what Dealers say :mad: but what you describe is exactly the same as I had. Floor it and misfires and then clears.

If the quotes a big one (never had that so dont know) I would still ask them to check the Stepper as this cured mine.

If it is valves (gulp) I'd expect it will be cheque book time and not change in your pocket.

Good luck.

[Rushy Racer]

I'm told it's the flaps in the inlet manifold so all told , when it goes in this Friday for new inlet, new inlet gasket and a set of plugs I'm looking at a bill of £760 +vat. Although the way the car went today on my 415 mile round trip to Ilfracombe I don't know why I am taking it in, it went like a train !!