I have a 93 LS with 140k. A year or so ago I started to get a hesitation upon acceleration. About 3/4 throttle, it just bogs down. Like bad gas. I switched to different types, octanes etc. Helps for about a week then back to it again. It has been getting worse now. Tried resetting the computer by unhooking the battery. Works like a charm for about a day...I have replaced the Spark Plug wires, EGR valve, Vacuum Tubes, O2 Sensors (fronts) and cleaned the rears, new air filter and plugs. No luck. Any ideas? Dealership did not experience enough of a problem to warrant any repairs because I was frank about the "list of could be's" and that I would not pay for trial and error diagnostic repair. Anyone had any Fuel filter issues? Catalytic issues?
I am desperate for answers..anyone had similar symptoms?

 

maybe fuel filter issue or clogged throttle body.

 

Any experience with either of those? I do some of my own work and the fuel filter should be no problem. What about the throttle body? Can I get to it and clean it myself.
Thanks for your help. No one has suggested the throttle body before.
Swap me the GS for my LS and we will call it a day...

 

daven3,

Have you run a good fuel injector cleaner ran through the gas yet? I used B-12 Chemtool but I have since read that the Gunk brand is the best based on ingredients (looking for forum, it was on another site), I have also heard that many people prefer Chevron Techron. Don't use any injector cleaner too much or too often as it can degrade the glue that holds the injectors together.
I would also recommend the fuel filter replaced if it hasn't been already. 140,000 miles means about 7,000 gallons has flowed through that filter, even high quality gas has some sediment that will be trapped in there.
I don't think it would be the catalytic convertor as these vehicles are among the best at low emissions (mine was almost too low to measure a few months ago), they apparently have a very good emissions control system. I was having hesitation problems that were remedied by the fuel injector cleaner, air filter swap, and transmission flush. I plan to have the fuel filter swapped out tomorrow.

GA400

 

Thanks for the advice. Sometimes you look so hard for the answer it was what i was thinking all along. I had a fuel filter ready to get plugged in and took it back. The dealership told me they have never had a problem. Should have gone with the basics first.
Thanks

 

daven3,

Look at this way, you have done a lot of preventive maintenance that will certainly help your performance and fuel economy. Trust me, flooring that V8 and getting pushed back in the seat is worth the time and cost

GA400

 

One part that is worth replacing although it is most often seen in low rpm part throttle conditions... is the throttle position sensor. These do wear out and can cause a number of problems.

Read through this thread and the one it references.
https://www.clublexus.com/forums/sho...threadid=58443

 

I I bought a 93 ls400 about 4 months ago with 93,000 miles on it. I think I have the same problem you are describing. When I first crank it up, the acceleration is strong and smooth. Then after a while of driving the car starts to feel a little sluggish. When I press down on the throttle it also has a little jerking sensation while accelerating. Almost like and engine sputter feel but the engine sound seems regular. Fuel injector cleaner seem to help, but for that tank of gas only. Thinking about a trans flush next.

 

I had a simular problem on my '94 LS. Turned out to be the main computer under the glovebox.
Dealer wanted $1400 for a rebuilt unit. I paid a parts place $400 to rebuilt mine. Had it ready the next day, easy to re-install. I had also changed my fuel filter first.

 

I had a simular problem on my '94 LS. Turned out to be the main computer under the glovebox.
Dealer wanted $1400 for a rebuilt unit. I paid a parts place $400 to rebuilt mine. Had it ready the next day, easy to re-install. I had also changed my fuel filter first.

 

i had a similar problem i had the induction service done at lexus and the problem went away......