Toyota Repair: pinging, gas additives, variable valve timing

Question
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Followup To
Question -
I have a 2001 Corolla CE with 120,000 miles (mostly highway).

About a year ago, I noticed that my engine was pinging noticeably at highway speeds under loads or going uphill.  Also, when I started the car in the morning, the engine sputtered when I put it in gear (standard trans) but it went away quickly.  I called the Toyota dealer and he suggested using premium gas.  

When I switched, the pinging almost totally went away, but then my Check Engine Light came on.  I went over to an auto parts store to have my computer read.  It said I had a misfire (P1349).

I checked with some forums and it was suggested that I add a injector cleaner to my gas, such as Seafoam or Techron.  I did that and also changed my air filter and cleared my codes.

The light stayed off for 3-4 tanks of gas (back to regular).  I kept that up for a while and then I had the code checked again, and I had the misfire coded again, plus another code said my catalytic converter wasn't working right so I had that replaced.

No light for about two months and not using the gas additives and back on regular gas (Chevron every other tankful), but it's back again.  The CEL came back on and I was getting a little bit of pinging on hills.  I added Techron for a couple of tankfuls of gas and changed the air filter, and the light went out after I changed the air filter.

Is this something I can do something more permanent (expensive?) or is there something else I can do?

Thanks.
Answer -
The P1349 is not a misfire code, it is a problem with the VVTi( variable valve timing) system, Toyota has issued a service bulletin regarding this code(TSB EG009-03) to correct this condition, have the dealer look it up,unfortunately the warranty period is for 5yr/60,000 miles but you are way beyond that at 120K.
But now, at least you know what the real problem is.
You may have some recourse if there is documentation at the dealership that you complained about this when the car had less than 60K on the odometer, in that case I would contact the service manager and try to get the factory warranty to take care of this very common condition, it's worth a try.

Followup-  

Thanks for the info.  I looked up the bulletin on the web and it had it listed for 2002 Celica exhaust system-sulfur smell.  Is that the same thing?

Do I need to have a Toyota dealer fix it, and what is it going to cost me?

Thanks.

Eric

Answer
No, the PO1348 DTC addresses the VVTi problem,which is service bulletin EG009-03, the excessive sulfur odor is another issue. The PO1349 trouble code needs to be addressed first before doing anything else and unless you want to experience somewhat of a nightmare I recommend that you have a toyota dealer handle this.