Hi again. Well, I ran into another problem with the 1994 XJ12 I am about to purchase. I asked the owner to get a pre-smog a week ago and it failed. It passed on the low rpms but failed on the high rpms. Anyhow, the guy at the smog station told him to run some tank cleaner through with a tank of gas and to bring it back. So he did that AND changed tio fresh oil, and when he took it in this morning it failed again but the numbers dropped considerably. So the next suggestion was to change all 12 spark plugs.

My question is do you guys think that will do the trick?

What I don't get is how this car could pass a year and a half ago, and now not pass when nothing has be altered? The car runs smooth and ya can't even tell it is on.

Any suggestions because I can't get a car that won't pass smog or I might be getting into a nightmare!

Thanks....

peace out,
daddylogan

 

Lots of possibilities. Air filters, fuel filter, plugs, wires, cap, rotor, 02 sensors, etc.