99 Toyota 4Runner SR5

I have a 1999 Toyota 4Runner SR5 with 102,000 miles. Recently, my SUV has been making a knocking sound and has been sluggish upon acceleration. I tried adding a fuel additive to get rid of the knocks, but that didn’t work. Next, I replaced the worn tires, but that did not work (but the tires really needed replacing, so it was good to get that out of the way). I then had the oil changed and the fluids topped off. Yesterday, the SUV simply quit. It would not start, but made the clicking sound which made me think I had a bad alternator or starter, but after seeing the check engine, battery and low oil pressure lights, I knew I had a problem. Someone mentioned that the problem could be a bad oxygen sensor, but since I have no idea of the inner workings of cars, I don’t know what that means. Could a bad O2 sensor prevent the car from starting? My fear is that the oil change folks did not put in enough oil and that I have blown my engine, but I sense that I would have known it if I had blown the engine.

I realize that this is a rambling message, but am hoping to give enough facts that someone can offer a workable solution. My plan is to have the 4Runner towed to the Toyota dealership in the morning so that they can tell me what’s wrong. I expect the problem to cost me in the four digit range.


Considering the oil change comment, and if this knocking was present at idle also, then I would strongly suggest you pop the hood, check the oil level, and pray that it’s not empty.

If there is no oil showing on the dipstick that clicking could be the sound of a starter kicking in and out due to its failure to crank over a seized engine.

Check the oil level and post back.

Thanks for your reply. I checked the oil earlier and it was at the “full” level, so it looks like the oil folks did their job.

That’s good. In regards to this knocking sound, is this more of a rattling type of sound that is not present at idle but only occurs on accleration?
If so, this is more than likely a pre-ignition rattle caused by a fault in the EGR system.

As to not starting and the clicking, this sounds (first off) like a weak battery.
If the battery is known for a 100% fact to be good, then I would inspect and clean the battery cable ends and check the alternator output.