Poor economy in '98 LS 400

[M.Yasir]

Hi

With the recent change of my starter motor (Starter motor changing)

I have been experiencing poor economy runs, earlier i used to get easily 350 miles (without hitting the reserve light) in a tank full but now i am getting 280 or max 300 when the reserve light hits on... and yes the check engine light is on

Car is fine while starting, fires right up idle at normal speed 800-900 RPM in Neutral gear and 600 RPM in Drive gear, I remember when i first took the car in the auto garage and when one of the gents pulled up the codes it was showing air to fuel ratio code... the OBD reader he was using was a tablet and a mounting device which plugs in the car maybe it was a Bluetooth reader

So if air to fuel ratio is the problem, from where i should start? before going to any garage... what i am looking here? is there a possibility that my air filter is gone bad, i am confident that my air filter is at least a millennium years old!

One more thing, while in the process of changing the starter motor, I was not able to arrange the manifold packing, so the mechanic used the old packing and applied adhesive, is there a possibility that it is causing the issue?

What else i am missing here? on some forums i read that by changing the oxygen sensors it improves? or is it my tires gone bad... i know it is about only 50 miles more of economy but you know that your car is not running up like it used to before, it feels like she is eating up fuel,

please help

 

 

[sha4000]

Since your air/fuel ratio is not correct the performance and mileage will definitely suffer. It could be O2 sensors but maybe you need to clean your MAF sensor. They make a spray specifically for cleaning them that you can pick up in any auto parts store. I think CRC makes it.

[billydpowell]

do us a favor and tell us what the trouble codes are... then we can "guess" along with you.... 

[M.Yasir]

you made me laugh billy

To be honest it is frustrating why because sometime the check engine comes on, sometimes it goes off..... anyway let me first buy a good OBD reader before assuming something

[billydpowell]

ok... waiting on you.. you going to use internet or local?

[M.Yasir]

ummm.... yeah most probably i will buy from internet... but unfortunately here in UAE there is no amazon.. so lets what i can find on some domestic websites here.. any suggestions for good OBD readers for lexus?

Bludriver

ScanTool 426101

BAFX 34T5

ScanTool 425801 OBDLink SX USB