Hey all, i have a 2000 S-Type V8 i just bought w/ 94,000. Think it has been sitting for awhile. Changed the sparks with ngk's and still have quite some lag. (but not as much as before, probably because it was misfiring) But is it a good idea to change fuel filter and use techron fuel system clean with full tank of 93 octane? (and of course an oil change) to see if that fixes the issue?

 

I've moved your question from General Tech Help section to the S-Type section for input from members with the same model.

If you've had misfiring, it's a good plan to read the codes as this will give a better indication of the cause of the poor running.

Graham

 

Could easily be bad coil(s) or an air leak. I strongly suggest stop changing parts but get tools. COP tester for coils but vitally an OBD tool with live data and start at LTFTs (see below).