I have a 1998 4Runner Limited with the vz5 engine vin code N with 180 k miles and has a misfire between 2500 and 3000 rpm. We took it to the local Toyota dealer and they said that the "bottom end" was messed up and suggested a used motor. I know these motors can go way longer. I have like everybody else gone to YouTube as my first source and found nothing to do with my problem. The tech report from Toyota did mention that the crank sensor looked messed up no details. The motor got new plugs and is running a little better but not where it needs to be. The timing belt is at 100k and it is time.. Anybody think this would me a good time to replace the sensor and the bottom pulley to eliminate that end of the mystery? Just grabbing at straws to see what works.

Before doing the belt and other components, I'd scan it for codes and then do a compression and leak down test. Those 3 things will tell you alot of info

Replace the sensor, sure. You may want to consider replacing the coil packs as well. Ignition coil. Whatever they're called for our trucks. These: More Information for DENSO 6731201

Sent from my SM-S908U using Tapatalk

I agree with checking the ignition coils and a compression test will help tell the overall health of the engine.


Sent from my iPhone using Tapatalk

Thanks for the ideas. I just ordered a set of coils. keep ya posted!

"bottom end messed up" is not a diagnosis you want to hear, they would have needed to remove the oil pan and inspected crank bearings to determine that, unless the crank has walked or play in it. Maybe the crank rotor is damaged or the crank sensor is damaged, and perhaps due to excessive wear in the bottom end, but I would want to see it before throwing a motor at it.

He could drain the oil. If bearings or thrust bearing are wiped it should show up in the oil.


Sent from my iPhone using Tapatalk

These engines are not known for lower end issues. Unless a PO ran the engine out of oil in the past..

Sent from my SM-A536V using Tapatalk

Had a very similar misfire problem, what the history on your plug wires & boots?

And if he needed to go deeper, op could do a oil analysis through Blackstone Labs. That will see parts smaller than the eye can see.
Between oil analysis and a compression check, and if need be a leak down test...that will give you a good health check on the motor.