MM8419

I wanted to know what spark plugs would you recommend for a 2009 ls 460?Also in addition to the plugs what would you recommend I get done to help get the HP restored?

aristo1987

Your question is very vague. Help to get horsepower restored? Well 1st you need to find the root cause of your problem. If you're losing hp it can be anything from spark plugs, fuel injectors, throttle controller, maf sensor, filters, engine oil and ignition coils and type of fuel or a combination of things. This is just naming some of the basics.

If you're really having issues. It could be the whole motor, cams, timing, lifters cylinders, crank etc.

Caflashbob

Try top tier gas. Unocal. Costco. Noticeable improvement in a couple of tanks.

you are running premium gas?

sdls

I can’t guarantee any power increase but a good starting point would be to run a fuel system cleaner like Techron, put in new OEM spark plugs, clean the mass air flow sensors, replace the air filters, and clean the throttle body. Beyond that if you feel you’re down on power you’d need diagnostic testing done to see if your sensors are working properly, a compression test to see if any cylinders are down on compression, and maybe an exhaust back pressure test. It’s never a good idea to throw parts at a car without knowing what’s wrong but basic maintenance can’t hurt.

oldred

These cars have very sensitive engine knock sensors. In addition to all the above suggestions, have a diagnostic test done and check the Knock Correction Learn Value (KCLV). There are two values - below and above ~3,000 rpm.

KCLV in the mid-high 20’s will be giving optimum ignition timing and maximum available performance (if the rest of the engine is in optimum condition).

KCLV below 20 will be pulling significant ignition timing and affecting performance. Bad gas will cause low KCLV, as will other factors like worn valve guides (so says Lexus).

If your KCLV is in the 20’s and the car is performing poorly, you have problems elsewhere.