dry-fly

I've got a 90' LS400 with around 180k on it that has been pinging for some time. It does it almost exsclusively under light acceleration. Se***s to be worse in the summer with the AC on. I've tried lot's of fuel treatments, put in a new air filter, no engine codes, I use premium gas. Any ideas?? Thanks.

Lexusfreak

I perform a 'major' tune up with top quality brand name parts to start with & have the injectors professionally flushed. Use NGK or Denso spark plugs.

HarrierAWD

A common cause of engine pinging is carbon deposit. Many top brand gas treatment like Techron or STP claim to remove it. From my own personal experience with my last car, only the Berryman Chemtool B-12 worked. You can find it at AutoZone. Just one bottle will do.

dry-fly

I've tried Berryman's, Seafoam, Redline, Techron......some of them more than once..

dry-fly

No more ideas?

T0ked

iTrader: (2)

Have you checked your timing?

dry-fly

No, that's one thing I could do.........

T0ked

iTrader: (2)

Pinging means detonation usually. Common causes are carbon deposits as mentioned already, but also faulty fuel pump/filter, timing. Pull your plugs and see if they are black (normal depending on how old they are), or have a sheen of silver on them (bad). That will show you how serious the problem is. Full tune up is in order.