janterry15

family has the car for a long time but I started driving it for 1.5 years now.

Each time I fill up it says 275 miles for full tank of gas. From what i have read, this car supposed to get 325-375 miles per tank.

I have changed the air filter, alignment, cleaned MAF sensor, pumped up tires, using 91 octane, changed spark plugs, and even seafoamed the car. It felt smoother and more powerful initially but now after a couple months, it is feels sluggish again. The car does smell like its burning richer, tho no distinguishable coloration in exhaust fumes.

The only thing I can think of is a bad O2 sensor, but there are no check engine light.

What other things can be causing such a issue? Even a road trip with the car from SF to LA and back, gets about 22-23 highway only.

DRACO A5OG

I see you have not mention Fuel Filter.

Remove the front O2S and post a pic of the condition. You can clean it with a torch if too fouled up.

Try some BG44K, it is Techron on steroids. Beware, if you do use it, use it in conjunction with a long road trip to get it out asap, stuff is very very harsh if it sits in your tank.

speedkar9

Get an OBDII reader and check your fuel trims and oxygen sensor readouts. Sometimes they could be a little off (I think the threshold is +/- 15% if I recall?) causing poor fuel consumption without the CEL. Also clean your mass air flow sensor, I found that made a reasonable improvement in mileage for my ES330 (although its still pretty bad @ 12L/100km).

Poor gas mileage has been a characteristic of the 4ES. There's a number of threads written about it already:

https://www.clublexus.com/forums/es-...4-es330-3.html
https://www.clublexus.com/forums/es-...nsumption.html
https://www.clublexus.com/forums/es-...is-so-bad.html

mmatheny

I get 26mpg highway doing 65-70 - I wouldn't call that poor for a 14 year old car!