LexusFan2

Hi,

I have a 2007 ES350 with 78k miles. For the past few days when I go to start the car in the morning, it will crank and start fine but immediately after starting the rpm will drop very low and the car will stall. I am able to restart again right afterwards and the car will stay running but the rpm needle will rev up and down from 800 to 1600 for the first 15-20 seconds. After that, it will go back to idling normally.

When driving the car, there is a slight but still noticeable hesitation when accelerating from rest or when accelerating to pass. I’ve also noticed a 2 mpg drop in my mileage. However, it idles fine while driving.

There are no check engine lights indicated in the dash. I run 89 octane gas and go to the same gas station for each fill up.

Any suggestions or troubleshooting tips would be welcome. Thanks.

jcat_350

Ever changed the fuel filter on it? If not, why don't you do that

If it's not the fuel filter, it could be the Idle Air Control valve, or a fuel pump issue.

oldgrump

You may yet get the engine check light ON but I would bite the bullet and get the car to a dealer or to someone with the expertise to troubleshoot your issue. This is the type of issue where the car should be hooked up to a scantool and the live ECM/sensor data looked at by a knowledgeable person. I would guess that it could be an MAF issue but it is strickly a guess and looking at the troubleshooting matrix there can be several other root causes for what you've described.
These cars have fly by wire electronic throttle control and do not have an Idle Air Control valve. They also do not have the old inline fuel filter......the filter resides in the fuel tank and is integral with the pump and is generally not a fun job to replace.