I've got a 97 3.4 T-100 w/ 96k and when I bought it it pinged even on premium. I ran seafoam threw it in the intake and as a gas additive on two occasions with no effect. I replaced the plugs with the ones recomended for the supercharger application (colder) now it runs on premium and only pings on hot days under heavy load or with the A/C on. If I use 89 it pings constantly when put under load between 2200 & 3000. I don't want to run on premium I'm cheep and premium isn't! What do I try next? I was tempted to replace the ox sensor but thats an expensive shot in the dark. <img src="/forums/images/graemlins/confused.gif" alt="" />

You can get the o2 sensor from URD for under $100 (they are good too, not the crappy universal ones) URD Denso O2 sensors scroll down for the application guide. You probly only need to replace the front one, if thats whats wrong. Check the MAF also (clean it maybe?). Also did you make sure the spark plugs were gapped right?

All that pinging and you're not getting a check engine light?

Maybe time for a dealer/professional check. My local dealer has a fuel injector cleaner offered for under $100. They could also check codes.

I bought a "top end" intake/valve cleaner kit from Gettel Toyota to try and help my doggy acceleration. It may have helped a little, but hat may also be wishful thinking.

My '96 has pinged since day one.
No matter what I do it pings.
Everything is serviced and working as it should.
The knock sensor kicks in and all is good.
With almost 200K I don't worry about it anymore.

Can someone explain what you all are talking about. Is it a ping like a bell or more of a thud. My truck knocks (thud sound) at idle sometimes. I just attribute it to bad gas because it doesn't always do it.

Also, what exactly does the knock sensor do? This may be a stupid question, but I though I would ask.

It kinda sounds like a spray paint can when you shake it. The knock sensor senses the knock and retards the timing.

So if the knock sensor is supposed to adjust the timing and make the knock go away. Is the knock sensor bad if the knock stays around for a long period of time or is something else to blame?

I think it can only retard the timing so much, but something is definently wrong, it should not ping at all.

Are you sure it is actually pining? I had a pinging like sound at about 2200 to 3000 RPM's and it turned out to be the heat shield on the crossover pipe. Over time the shield will lossen up slightly and rattle under load. It may not be obvious by looking at it or even grabbing it. I took a screw driver put it on the top seem, and tapped it lightly till it moved back a quarter inch or so. Now it is quite as the day I bought her. I don't know if this is your problem but it's worth a shot to take a look.

Ryan

The ping goes away when I use premium, so I don't think it would be a loose heat sheild. It sounds more like a timing probleme, to mutch advance between 2000 & 3000 rpm.