4Runnerman

I'm having a pinging problem with my 1998 4Runner with 45,000 miles, and I'm wondering if anyone has any suggestions. I run regular 87 octane gas along with an Amsoil air filter. It doesn't seem to be a problem when the truck is cold, but when it is fully warmed up it will ping constantly at highway speeds when applying the throttle(unless you really open up the throttle).

Has anyone else had this problem? Any ideas what could be causing this?

Please help.

SLC Punk

Is your truck supercharged?
If so go to Gadget's website.

If not, try changing your fuel filter and put in premium gas.

Dr. Zhivago

Your MAF sensor is most likely dirty. You need to clean it and your throttle body.

Use some non-residue electronics cleaner to clean the MAF and some Fuel Injector safe cleaner for the Throttle body.

Hope this helps.
G

4Runnerman

I don't have the supercharger and I have never replaced the fuel filter, but I did clean the MAF sensor and throttle body a few months ago.

Do you think it could be related to the O2 sensor? I have the single catalytic converter model and have never had the check engine light come on. Has anyone replaced their O2 sensor as regular maintenance? If so, at what mileage?

Thanks again for the help.

rimpainter.com

The O2 sensor should trip the CEL if it fails. Try the fuel filter idea, it is really easy. Get your filter from TOR (Todd) here on the boards.

Motorvac is another idea (I think that is what it's called) - it cleans out the cumbustion chamber, etc of carbon deposits. It's $100 or so. I would of course check the engine over for vacuum leaks, etc.

MTL_4runner

You definately need to replace your fuel filter if it is a 1998 !!!!
I really don't think you have a bad O2 sensor.....that should set off a CEL.

Things to do:
Make sure your air filter is cleaned and reoiled.
Run a full tank of premium gas with some techtron injector cleaner.

It is definately a leanout condition (ie not enough fuel).
So check all the areas of fuel delivery for your problem.

4Runnerman

Does anyone know if there is a normal maintenance schedule for replacing the fuel filter? I haven't gotten a Toyota Maintenance Manual for my truck yet, but from what I understand Toyota's fuel filters hold up very well.

What is the general consensus for when to replace the fuel filter?

Thanks again for all the help.

FattyCBR

According to Toyota it's a never replace item, I replaced mine at around 75k after I supercharged. If you have 45k I wouldn not change it, it hasn't gotten dirty that fast, unless you've been buying gas in Mexico or South America. Also the pinging could be due to carbon buildup in your combustion chamber. You might also try testing your TPS and your MAF to see if they are readign correctly.

MTL4Runner-

How can you definitively say the problem is a leanout problem? He could very well have carbon buildup in his chamber.

MTL_4runner

How many cases of carbon buldup have you seen on 4runners?
I myself have seen very few but you are correct, that doesn't mean that is not the case here.

As for the fuel filter that is total hogwash from Toyota.....
Kinda like lifetime sparkplugs....how much do you trust that BS.
I suggest every 4 years or so.