Dealer Just Adjusted Throttle Body, Now Milage Seems Worse

[docmas]

Seemed like steering wheel and car vibrated a little too much at idle, dealer "adjusted" the throttle body. Now it seems like my milage is down maybe 2-3mpg. Could this be connected somehow? I would think the adjustment would have no impact or reverse of what happened. I still have extended warranty on my 2002 LS430 through March, so I can bring it back in if need be.

Thanks for you input,

Adam

[MidNightGS430]

Seemed like steering wheel and car vibrated a little too much at idle, dealer "adjusted" the throttle body. Now it seems like my milage is down maybe 2-3mpg. Could this be connected somehow? I would think the adjustment would have no impact or reverse of what happened. I still have extended warranty on my 2002 LS430 through March, so I can bring it back in if need be.

Thanks for you input,

Adam

Depends how high they adjusted the idle!? It shouldnt idle above 1,000 RPM's maybe 1100 at the most.....Mine idles at around 900 rpm and its just fine. But the rough idle could be bad plugs or dirty air filter etc. its hard to say. I know that adjusting the idle is a quick fix for the rough idle, But not a resolution to a potential problem that may exist.

[IS400]

Seemed like steering wheel and car vibrated a little too much at idle, dealer "adjusted" the throttle body. Now it seems like my milage is down maybe 2-3mpg. Could this be connected somehow? I would think the adjustment would have no impact or reverse of what happened. I still have extended warranty on my 2002 LS430 through March, so I can bring it back in if need be.

Thanks for you input,

Adam

Sounds like they did something to enrich your mixture. You will have a higher idle and use more fuel sitting at lights and warming up in the a.m. and such.

You should have them pull the codes and make sure they are not just feeding you along to get from paying for an expensive repair under warranty.

Have them put it at the factory spec idle speed and see if it is still smooth. If you cannot stack champagne glasses on the intake three high in a pyramid while it is in park and running, you do not have the lexus quality you deserve.

Another thing to think of is the motor and transmission mounts. Putting new mounts in my 1st gen made it feel as smooth as a new lexus again.

Good luck!

[docmas]

It idles at 400rpm or so, from looking at tach, so don't think they raised that. Guess I'll go back again and see what they have to say. If I need a new tb, I'm sure they'd love to do it, as Lexus pays them for the repair. Same thing with motor mounts, though they said those still seemed good. At 74,000, I would think they still would be. Just looking for advice on what to tell them when I take it back.