My IS 300 AWDI recently just purchased her a couple of weeks ago. Pre Owned at a Infiniti Dealership. Was told it was a Trade-In because the Owner wanted a SUV. After a couple of days of owning this Car i noticed that Tachometer fluctuates when the Vehicle Starts up.But now any time i start the vehicle and the Car in Different Gears it revs high in reverse, parked or drive.Also there have be times that whiles driving , the Gas pedal feel very stiff and I have to press down on it hard for the Vehicle to accelerate. Took it to a Lexus Dealership twice and had two Mechanics on two different occasions test drive the vehicle with me. They kept my vehicle for a week and said they couldn't find a problem. I was told that when Lexus first start up in the morning the tachometer revs high for a bit while the vehicle warms up and that was normal. The Dealership loaned me a 2023 ES and the Mornings it wasn't doing that. Two weeks ago whiles on the Highway the Gas pedal was hard to push down then it clicked into a normal Mode and the Vehicle took off! I had to slow down. I've been driving the IS. I didn't trade in my Camry, so she has been parked. I just sold the Camry, whiles driving her to Carmax there was a smooth acceleration. I know they have two completely different drive trains. But something is a little off with my IS. Does anyone know why the Tachometer & the Gas Pedal is acting strange? Because the Stealership can't find the issue.

 

Welcome. Given that there is throttle-by-wire in this car, the only real explanation for a stiff gas pedal I can think of is an obstruction in the floor of the car behind the gas pedal. Have you checked for anything of the sort?

 

I've checked nothing in the way. Something is off. But thanks

 

Right, I was just thinking that the way you described it "clicking" into normal mode, plus the fact that other cars exhibit no such behavior - something is different about the physical pedal in your car, I reckon.

I've owned 3 ISes now, and none of them have behaved like what you described.

Could it be an issue with the floor mat? Maybe there is something sticky on the gas pedal itself?

If you think it's electronics-related, maybe try disconnecting the battery for about 30 minutes to reset the computer. Personally I'd try all the other non-battery options first.

 

yeah it's hard to explain. But the Tachometer Fluctuating when i put it into different gears is strange as well. I'm going to a Different Lexus Dealership this weekend to see what they say. This is my 3rd Toyota Product and for some reason I haven't had luck with any of them. Next time I'm going to a different Manufacturer

 

The "stiff" pedal just does not make sense to me. Never heard of that on these cars, and I've been on the forums for several years...

Hopefully a different dealer can help you out. I am still leaning towards it being an issue of something physically messing with the gas pedal. That could cause unpredictable responses from the pedal, the RPM to rise and fall randomly because the pedal is being pressed not by you but by whatever random object is interfering with it, etc. Maybe try removing all floor mats and other objects from the car and see if that helps. Sorry to sound like a broken record, but I can't think of any other reason the pedal response and stiffness would be changing like this. It's not like the car has any way to push the pedal back on you like some others out there - it's more old-school lol.

Also, I will say, the throttle calibration on these cars is not super aggressive like on some American cars or BMWs. It does take a little more pressure to make the car wake up and go for a pass.

 

I hear you, and appreciate the response. The first Lexus Dealership I sent the them some things I saw on YouTube. With things people have had with their older IS vehicles. Like " Pedal Position Sensor" , "Faulty Sensors" "Power train Control Computer" Vacuum Leak from Dirty Fuel Injectors" etc. I will admit when I first start having these weird issues I got a fuel injection cleaner from Walmart that tells you to put in the Gas Tank that has helped the vehicle. But still there are unexplained things.