I just got a 4runner and this was already installed. What's the purpose? Looked em up and these things are really expensive. What's the point? I've been too I can use this to help with fuel economy? Anyone know what's up with these? Thanks!

 

ur truck probably had a supercharger on it, or maybe turbo if someone was trying to monitor the A/F ratios....thats the only reason to put one there, unless the previous owner thought it was really cool to add useless gauges.

 

I don't think it did. Just a 1990 4runner with a 22re and a 5speeed. If it did I wish it was still

 

if its a wideband a/f ratio gauge then its like a $200 gauge and there very nice to have even if it doesnt have boost running through it. if its a narrow band gauge then its worth like $20-$40, i really want one for my celica becaust of all the intake mods it has but cant afford it

 

It's wide band. I don't know why but it reads strange (to me) under normal throttle and idle it reads right around 14.7, but when I'm cruising and let off the throttle without engaging the clutch it reads 22.4(gauge maxed out) hmmmm. I've been told these are good to learn to drive more economically.

 

14.7 is perfect for idel, thats what you want for a AFR at idel. when your at WOT it is going to read less than 14.7 which means it is richer. and when you let off the gas and slowing down under compression it is going to read above 14.7 which means little or no fuel is going to the motor, thats perfectly normal

 

warpigg knock it off. Only warning I give. I cleaned the thread up.

If runs lean when you let off because of fuel cut by the ecu. Its running just fine and normal. 14.7 is stoich= normal air to fuel ratio. The ecu tries to keep it 14.7 under most driving conditions till you hit WOT. Then it hits 12 to keep it safe.