I was wondering if using regular gas instead of premium would trigger a P0420 and P0430 code? Anyone had this issue?

 

Those are cat converter efficiency codes. Offhand I don't see how octane rating would play in.

I'd stay with manufacturer recommendation but if you wanna experiment your car has knock sensor which detect knocking/pinging...which might well result from the lower octane... and automatically retard the ignition timing to eliminate it. As a result you might feel a loss of power and use a bit more gas.

If you are a very gentle driver and conditions are ideal you might not get any pinging or knocking

Cheers
DD

 

The reason why I asked was because someone borrowed my car and put in 87 or 89 octane and it was throwing a P0420 and P0430 code. I filled it with premium fuel today and cleared the codes right after. Drove her about 50 miles and no codes so far. And yes,I'm a fairly gentle driver when it comes to my Jags.

 

Interesting.

I also wonder if it was a difference in fuel *quality* rather than a difference in *octane rating* ?

Let's hear what others have to say

Cheers
DD

 

I have been running 89 octane for three years and no problems. A XK8 forum member has been using 87 octane in his 02 XK8 for at least that long. I think if it's a fuel problem something other than octane rating is at fault.