psdvette

My ES300 has very slow acceleration. It wasn't this way when I bought it at 158k in 5 years ago, but it's been this way for over 2 years I'd guess. Currently has 195k on it. Finally getting around to fixing it.

In this video this is me with gas pedal to the floor and on a level street. 10 seconds+ to 40mph, probably 15+ to get to 60 had I kept going.

http://s1263.photobucket.com/user/ar...24091.mp4.html

1998 Lexus ES300
- 195,000 miles
- new plugs, wires, air filter this week
- exhaust is all new 3 years ago from headers back to tail pipe
- transmission fluid and oil changed within past 2 months
- The car does hiss on full acceleration so vacuum leak is likely, just wondering if it could make my acceleration this bad. I've been unsuccessful at tracking down the leak
- The car also does idle a little rough occasionally but I believe that is due to the rear motor mount being worn out (it does seem worse when on certain inclines)
- Compression tested at 210-215 on all 6 cylinders

I did a good amount of searching around. I've seen torque converters/transmission issues mentioned. Clogged cat/exhaust. Vacuum leaks. 02 sensors. Knock sensors. Clean the MAF or replace fuel filter. Lots of possibilities.

Just wanted to see if anyone had a good guess based off the video. I'll probably cave and take it in soon to a shop rather than mess around with it myself too much more.

ES300doc

Hiss on full acceleration would be an obstructed exhaust. Most likely a clogged Cat.

You could confirm this by disconnecting the pipe in front of the converter, move the pipe over and run a bolt thru on the opposite flange to secure it and take for another test drive.

The only other thing could be dragging brakes but you would have gone thru several sets of pads by now.

ES300MM

Are you getting any check engine codes? I'd start with the simple stuff first. Clean the MAF, check intake hoses, make sure none of your sensor connections are unplugged. Run some injector cleaner thru the tank. Then look to change fuel filter, check/replace throttle position sensor. I doubt it's your exhaust/cats. Mine has 200k and my cats aren't plugged up at all.

ES300MM

Especially since you have a new exhaust system. No way that's plugged unless you have been using leaded gas or something. Also clean your idle air control valve and your throttle body. If none of that works...When was your timing belt changed last? It could have slipped a tooth and your timing could be way off.

psdvette

I have ordered an exhaust pressure tester and will try that first. Even if it shows no problem, at least I'll have another useful tool. I too thought it would be odd my cat would go bad so soon although it's not an oem unit, it's a Walker brand I got from RockAuto and installed. Then I'll check the rest of the suggestions. I have seafoamed it via tank and booster line before as well.

Timing belt was done about a little over 2 years ago at 182,000 or so along with water pump. I actually have been thinking lately that it seemed slower ever since that time, so if I do take it back to the shop that does all my work, I'll make sure they check the timing.

Thanks.

Bumbobee

My knock sensors gave me ****ty acceleration and it's better now after replacement.

ViPeRs103

Did you replace the sensors under a code fault or just for the hell of it? And how many miles did you do this install at!?

Bumbobee

I had the knock sensor code, see my other posts and thread. Basically all these things failed close to the span of each other.

Transmission rebuild 240,000 km
Knock sensor, oxygen sensor, variable valve timing solenoid all went at around 265,000 km

morphh

Check if the throttle cable is opening throttle plate full when u floor the pedal.

Hayk

iTrader: (1)

I like this idea. Seems like a mechanical problem between the gas pedal and the throttle/transmission cables.

hzt30

Hook up a scan tool and look at both upstream A/F sensors while flooring the accelerator and going up a hill. If both sensors go full rich then it is not a fuel delivery problem. Check for a restricted exhaust and timing.

Wht95scort

Time for a trans.

mitmaks

When I read transmission fluid and oil changed that makes me think you don't know whole lot about cars.
In video seems like its accelerating just fine and looks like you're bit too hard on the car. Let it accelerate naturally, don't punch it-it does car no good.
I would make sure transmission fluid is in proper range (meaning it's not over/underfilled) and is right fluid for this car. Plugs need to be NGK as these cars are picky to fluids/parts you use on them.

mitmaks

ES300MM

This is bad information. You can "punch it" and it doesn't hurt the car. This car is accelerating terribly. Also you don't have to use NGK plugs. I replaced mine with Denso and mine runs perfect on them.