99 Gs300 Sluggishness

[sfm4103]

My 99 GS300 is sluggish when making a turn and with acceleration after slowing down. It's like the engine bogs down, but returns to full power in about 3 to 5 seconds. I get good power accelerating from a standing start. My GS has 120,000 miles. Spark plugs, air filter, and MAF sensor have been replaced recently. ECU has been reset and I've tried it with the VSC off.

Other than these problems, the car runs great. I'd appreciate you lettting me know if you have any ideas what might be causing this. It is getting dangerous to drive this car!! Thanks

[djspawn00]

drop in fuel pressure maybe? do any TCS lights flicker?

[sfm4103]

drop in fuel pressure maybe? do any TCS lights flicker?

Not sure what TCS is, but no lights flicker

[lagleigh]

drop in fuel pressure maybe? do any TCS lights flicker?

Not sure what TCS is, but no lights flicker

I have a 98 GS300 and I have the same problems. I also have problems when it is cold with the car not picking up speed. It's almost like there is something wrong with the transmission. After taking my car to the shop many many times I was finally told that it was because when the car is first purchased the first owner trains the car to it's drive pattern which is sluggish during take off and on occasion. That does not sound correct to me.

[smooth1]

Could be several issues, the catalytic converters could be clogged or flowing poorly, you may have dirty 02 sensors. Sometimes when they get dirty, they don't read as well, and may be making the a/f too rich, or it could be bad fuel injectors or a fuel injector leak. These are the fuel side problems it could be. On the electrical side, you may have a coil problem, wich may not be producing enouph juice under acceleration, or may be taking a bit longer to charge up, or if you had a maintence service lately, they may have miss gapped the plugs, or not gapped them at all. On the air side, just because they replaced the air filter, doesn't mean you don't have a clogged intake, or dirty throttle body. I would check the air intake ducts and just make sure they are all clear and clean. then open the throttle body up and give it a good look over and cleaning if you can.

[sfm4103]

Could be several issues, the catalytic converters could be clogged or flowing poorly, you may have dirty 02 sensors. Sometimes when they get dirty, they don't read as well, and may be making the a/f too rich, or it could be bad fuel injectors or a fuel injector leak. These are the fuel side problems it could be. On the electrical side, you may have a coil problem, wich may not be producing enouph juice under acceleration, or may be taking a bit longer to charge up, or if you had a maintence service lately, they may have miss gapped the plugs, or not gapped them at all. On the air side, just because they replaced the air filter, doesn't mean you don't have a clogged intake, or dirty throttle body. I would check the air intake ducts and just make sure they are all clear and clean. then open the throttle body up and give it a good look over and cleaning if you can.

Thanks for taking the time to lay out what might be causing the problem. The problem is intermittent. Does that eliminate any of the issues you mentioned? Besides working on the air intake ducts and cleaning the throttle body, if it were your car, what would you repair or replace next? Thanks again Smooth 1.

[smooth1]

Well, intermitten could mean that these symptoms occur only under certian circumstances,you just may not have realized what circumstances create the condition.

As I can't test drive the car and feel or see the symptoms myself, I can only read your post, which I just read again, Your issue is when you take your foot off the gas to slow down, then as you re accellerate the car boggs down and then returns to power? If that is the case, I apologize for my first diagnostic. I thought it was an acceration issue.

I think you have a bad knock sensor. It may be reading rich and retarding the timing.