Can anyone read these spark plugs?

[Costas00]

These came out from my ford fiesta 1.3 liter MY2007.
Vehicle mileage: 120k miles
Miles on plugs 10k
The car runs 80% of the time on LPG and 20% on petrol.
Two of the plugs have a redish color and the other two are more of a white-grey color
I did some long trips during the summer with outside temps up to 110F. The small engine really struggles with the a/c on at highway speeds. Coolant temps with obd reader in the summer up to a constant of 225F. I was thinking if the plugs show signs of overheating (red color). I have no significant coolant loss, maybe 200ml every 3000 miles.
The engine runs smoothly on petrol. On lpg I have some mild misfiring at idle but other than that the engine runs and pulls fine and gets decent mpg even on lpg.
P.S. I have zero oil consumption

 

[Kira]

Are all 4 plugs identical (same heat range)?

 

[Costas00]

Are all 4 plugs identical (same heat range)?

Yes they are all the same

 

[atikovi]

On lpg I have some mild misfiring at idle

Maybe the two cylinders with the lighter plugs are running lean at idle?

 

[IndyIan]

Wild guess but it seems the propane isn't getting to all 4 cylinders equally, to my eye 2 are rich as they look brown to me, and 2 are lean.
I don't think I've seen an overheated plug though?

 

[FZ1]

These came out from my ford fiesta 1.3 liter MY2007.
Vehicle mileage: 120k miles
Miles on plugs 10k
The car runs 80% of the time on LPG and 20% on petrol.
Two of the plugs have a redish color and the other two are more of a white-grey color
I did some long trips during the summer with outside temps up to 110F. The small engine really struggles with the a/c on at highway speeds. Coolant temps with obd reader in the summer up to a constant of 225F. I was thinking if the plugs show signs of overheating (red color). I have no significant coolant loss, maybe 200ml every 3000 miles.
The engine runs smoothly on petrol. On lpg I have some mild misfiring at idle but other than that the engine runs and pulls fine and gets decent mpg even on lpg.
P.S. I have zero oil consumption
View attachment 186533

Up your petrol till the misfiring stops.

 

[ripcord]

Is the propane system in your car a factory one or an aftermarket add-on? If not, are you using the same plugs and gaps with propane as the car originally called for with gasoline? Propane engines typically use colder heat range spark plugs and use a narrower gap. You might try experimenting with the gap to achieve a smoother idle on propane and hopefully eliminate the miss. I would try in the range of .65 mm to .9 mm. If the plugs are already a colder heat range than stock, you might try going one step hotter and see if that reduces the fouling, but beware of pre-ignition.

 

[Dave P.]

Rotate plugs when you rotate tires and you'll be good to go!

 

[Passport1]

They look ok but two of them been out in the sun too long.

 

[totegoat]

Since the plugs are out, I'd replace them.

 

[IndyIan]

Rotate plugs when you rotate tires and you'll be good to go!

Eh, you might have to rotate the pistons too... I guess I've seen most engine carnage on 2 stroke snowmobiles, where a lean cylinder can become a holed or seized piston.
White white plugs in a 4 stroke still would make me very nervous, but maybe lean burning propane doesn't run hot enough to damage anything?