bad gas mileage - Toyota Nation Forum : Toyota Car and Truck Forums

irishjay · 01-22-2011, 01:53 PM

My '92 4runner is getting terrible gas mileage.The plugs were changed a while back and I've been running Lucas through the fuel system.
This helped a little at first but recently it seems to have gotten worse.I do feel a bit of a "stutter" while driving at a steady speed.
Could this be a timing issue? Or possibly an electrical problem?
Any help is greatly appreciated!!

jetwhine · 01-22-2011, 03:25 PM

irishjay,

It might be time to change the O2 sensor. Get a denso if you decide to change it. The O2 sensor might be sending bad signals to the ECU. You will not have a check engine light with this problem as the sensor is still sending a signal, the ECU does not know a good signal from a bad one, the only thing it knows is if it is not sending a signal at all.

irishjay · 01-23-2011, 02:11 PM

Thanks jetwhine,
You've been very informative to my inquiries. I did consider the O2 sensor,but was hoping against hope that it might be something(less expensive)else!
On that note,maybe you can help me with another issue.My wife has a '96 Lexus(ES300) and it's been running rough.I had the the codes pulled and it was determined that I need a new O2 sensor and that the 5th cylinder is misfiring.I was told that it was probably the coil for that cylinder.Can you tell me which one is the 5th cylinder,and,how difficult it will be to change that.
Again,thanks for your help

jetwhine · 01-23-2011, 11:49 PM

Irishjay,

I am not familier with the Lexus, But I would look into changing the "COP" coil over plug first. This just might clear up the O2 sensor problem. If it does not then go for the O2 sensor. I'm not sure but does your wife's rig have the 4.7L V-8. The coil is not hard to change considering the access on your rig. Is your engine transverse or inline. There is a Lexus forum they will be able to help you better with which is #5.

99blackSE · 01-24-2011, 09:03 AM

Quote:

Originally Posted by jetwhine

Irishjay,

I am not familier with the Lexus, But I would look into changing the "COP" coil over plug first. This just might clear up the O2 sensor problem. If it does not then go for the O2 sensor. I'm not sure but does your wife's rig have the 4.7L V-8. The coil is not hard to change considering the access on your rig. Is your engine transverse or inline. There is a Lexus forum they will be able to help you better with which is #5.

I believe the 300 in the model name should mean it's the 3.0 litre V6.

ZAchole · 02-02-2011, 01:08 PM

Don't quote me, but I believe #5 is on the front of the motor, far right side. It's just like a camry.