R75 V8 Misfire / Running like a pig when hot

Hi All

New member so please be gentle...

I have just purchased my 5th Rover 75, the latest being my 2nd v8, I guess that makes me an enthusiast. However, my 04 75 v8 that I have just purchased runs fine while cold and under normal conditions but following a trip through London yesterday it started to run like a pig in heavy traffic (to the point I nearly fumbled around for my breakdown cover card). The temp gauge did not register abnormal temp and I could hear the fan cutting in and out but undoubtably once I got going again everything seemed better albeit not perfect until I started again this morning from cold. It ticks over warm at around 500 but this varies a lot but from cold it's what I would expect a constant 1k or there abouts.

Not sure what the cause can be, I did think coils but I am no mechanic, it's only done 28k.

Thanks for reading and Help!

Chris

We've all had a bit of that - get's a little warm under the bonnet sir. Once you get going again it tends to disappear. Become a full member and you will learn many things young Skywalker.

Fuel evaporation, coils, plugs perhaps,

WELCOME :D

My immediate thought is overheating under the bonnet,

Remove the sound deadening heat retaining carpet under the lid.

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Quote:

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Originally Posted by clynch26

Hi All

New member so please be gentle...

I have just purchased my 5th Rover 75, the latest being my 2nd v8, I guess that makes me an enthusiast. However, my 04 75 v8 that I have just purchased runs fine while cold and under normal conditions but following a trip through London yesterday it started to run like a pig in heavy traffic (to the point I nearly fumbled around for my breakdown cover card). The temp gauge did not register abnormal temp and I could hear the fan cutting in and out but undoubtably once I got going again everything seemed better albeit not perfect until I started again this morning from cold. It ticks over warm at around 500 but this varies a lot but from cold it's what I would expect a constant 1k or there abouts.

Not sure what the cause can be, I did think coils but I am no mechanic, it's only done 28k.

Thanks for reading and Help!

Chris

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Hi and welcome Chris

:cool:

when you were stuck in the traffic - did you switch off at all and restart? because pretty much all cars will then run a little rough due to heat soak evapourating the fuel.

Otherwise - yes it could be a coil pack breaking down but unless you're unlucky that would normally tend to be one cylinder at a time rather than general misfiring and poor running.

Idle at 1000rpm is too high though - even from cold or soon after, it'll settle below that and eventually sit at around 600-650 rpm at idle (or should do).

I think keep using the car in general driving and see if its a repeat general problem or only happens when car fully warmed up and then stuck for a while in stop start traffic situations.

As mentioned, removing the under bonnet insulation does help a little with heat dissipation.

Thanks for all of the posts so far on this,

Looks like I will remove the insulation from under the bonnet and see how i go. I didnt stop the car and restart while in traffic for fear of not getting it going again, i knocked it in and out of drive as i stopped and started for fear of it stalling while stationary. Incidentally the exterior temp displayed was much higher the real temp outside and i suspect this was due to the tropical conditions under the bonnet.

I would describe the car when hot and on tick over as 'hunting', with the engine going from barely running to around 500 rpm and back again.

Ive had this problem, when I was stuck on the M27, car was very lumpy whilst edging along in the traffic but once going it cleared up and I was treated to a massive wave of heat emminating from the dash board

Does removing the insulation make the car much noisier?

Yep that's it, i had to put the air con on cold, i did think its was rather odd in mid Nov!

I wondered about the noise also, i guess i will find out soon enough