Misfire issue

[Gandi69]

Wonder if anyone can shed some light on a strange little misfire I’ve got on my 182. When started from stone cold at around 1500rpm ish (with the lightest sniff on the throttle) I get a misfire when clears after maybe 30 seconds or so once the engine has a little heat in it. The misfire doesn’t come back either until the car is started up from stone cold again.

Plugs are relatively new (6 months old or so and under 2k miles on them)
I’ve done the obligatory leads and coil pack as I had them on the shelf and I’d been meaning to change them as the leads and coil were original 15 odd year old items.
Lambdas are knocking on a bit in age now, think I replaced the pre cat one about 7 years ago.
Injectors whilst they are all original all resistance check at around 15.3-6 ohms.

Not getting any fault codes what so ever so I guess im left with looking at live data to see what is going on?

Coolant temperature readings I’ve had a look via my cheapo diagnostics and seem to be about what you’d expect to see though I’ve got a new sensor on the shelf to fit if need be.
Mpg is fine, other than this issue the car drives just fine and pulls well etc.


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[HenryG]

I have had this problem only happened in the first minute or so then was fine. It was the Lamber sensor that need replacing on mine. There is a rumour that shell vpower throws them off quite quickly.

 

[JamesBryan]

Pre cat lambda I'd say.

 

[Gandi69]

Didn’t see there was replies to this as I’ve not logged in for a while. I’ve put a new pre cat lambda on it and still no change. I’ve been using only v power and Tesco’s 99 since I’ve owned the car which is 10+ years and never had an issue with either. The only thing I can think of is that the fuel might be going “off” as the car doesn’t get used much any more. Maybe throw some fresh in and see what happens. Not the end of the world to be honest, if you give it a bit it clears


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[Coops Mk1]

My 182 does this sometimes but not all the time, I always use 97 or above RON fuel, currently ESSAR 99 as local place is that now but if out and about BP or Shell etc etc.

It can do it on any tank of fuel from any of the above, so I have always just put it down to slight impurities in a certain batch of fuel, and I rattle through enough of the stuff doing 15K ish a year with the car as my daily driver.

never worried about it really