the car keeps bucking :(
07-13-06, 03:35 PM
#16
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Originally Posted by dejacky
There are others here with more mechanical experience than me, but when was the last time you changed your timing belt, drive belt, timing belt tensioner, water pump, oil + oil filter?
07-13-06, 04:00 PM
#17
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ah. a vacuum leak. do any of you think it might be a catalytic converter problem?
cuz when i shift to third that the bucking starts, i hear and feel popping noises.
and yes OLT, its got some TEXAS in it. hahahaha.
cuz when i shift to third that the bucking starts, i hear and feel popping noises.
and yes OLT, its got some TEXAS in it. hahahaha.
07-13-06, 06:04 PM
#19
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Just squirt some TB cleaner down metal tubing attached to the vacum hoses leading into the throttle body by squriting some TB Cleaner down them. There are 3 small holes that lead into the TB and they could have gotten stopped up.
That's what happened to me when I cleaned my TB for the first time.
The gasket between the TB and the manifold is a metal gasket.
Good luck on the fix
That's what happened to me when I cleaned my TB for the first time.
The gasket between the TB and the manifold is a metal gasket.
Good luck on the fix
07-13-06, 08:32 PM
#20
Ok so I cleaned all the hoses and pipes, car still runs the same. I tried unplugging the MAF harness while the car was running and it still ran the same. Does that mean that my MAF is bad? Or does it mean I have a bad wire going to the MAF? I can't really tell because the wires just go into a bundle after the harness.
07-14-06, 05:02 AM
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Originally Posted by bmatsu
The gasket between the TB and the manifold is a metal gasket.
07-15-06, 05:45 PM
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Okay I have now covered every suggestion that has been thrown this way. Could this by any chance have something to do with the automatic transmission???
Simon my car has had the cats removed a couple of years ago so that may not be your problem either.
Simon my car has had the cats removed a couple of years ago so that may not be your problem either.
07-15-06, 07:01 PM
#25
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engine problem
I would say you should "give up". I did and took it to the Lexus dealer for diagnosis. Once they TOLD me my fuel system, what I was sure was in the crapper, was OK, I was back in the hunt. Can you get to a dealer? You seem to have done everything immaginable and you deserve credit for your effort.
My SC400 wouldn't start cold and when it did it ran really ragged till I nursed her to warm her up. Then somtimes she had a bad high rpm miss. Not always. My mech said that it sounded like I had a "WEAK" spark that supported low rpm. Well he was correct. Fixed the problem with a used igniter module. My milage has gone up 3 mpg, as well.
Try this if you have a V8: When she is running rough, pull one coil wire and start the car. It will run on four cylinders and sounds like it is. Steady thump thump thump and giving it the throttle it gets rpm slowly. Then try the same with the other coil removed. They should both run the same. If one coil runs noticably better it is the other ignition system.
Spark plug wires can cause your symptoms. Especially a shorting coil wire. You can check this by running your hand over each wire with the engine running. Yes, it will give you a serious startle. You said you were desperate, right. If your wires are ok you won't notice any change in your posture or location. It works and I have found many a bad wire doing this.
Pull each wire out of the distributor and see how long of a spark you can draw. It should be bright blue and maybe orange and "snap" nasty about three quarters of an inch min. Blue and wimpy at half an inch means the spark will give your symptoms. GAZI ALI can fix you up with whatever you need.
Hope this helps.
John
My SC400 wouldn't start cold and when it did it ran really ragged till I nursed her to warm her up. Then somtimes she had a bad high rpm miss. Not always. My mech said that it sounded like I had a "WEAK" spark that supported low rpm. Well he was correct. Fixed the problem with a used igniter module. My milage has gone up 3 mpg, as well.
Try this if you have a V8: When she is running rough, pull one coil wire and start the car. It will run on four cylinders and sounds like it is. Steady thump thump thump and giving it the throttle it gets rpm slowly. Then try the same with the other coil removed. They should both run the same. If one coil runs noticably better it is the other ignition system.
Spark plug wires can cause your symptoms. Especially a shorting coil wire. You can check this by running your hand over each wire with the engine running. Yes, it will give you a serious startle. You said you were desperate, right. If your wires are ok you won't notice any change in your posture or location. It works and I have found many a bad wire doing this.
Pull each wire out of the distributor and see how long of a spark you can draw. It should be bright blue and maybe orange and "snap" nasty about three quarters of an inch min. Blue and wimpy at half an inch means the spark will give your symptoms. GAZI ALI can fix you up with whatever you need.
Hope this helps.
John
07-15-06, 08:34 PM
#28
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Trust me man, my '95 SC400 does the same thing and I get SO incredibly close to just selling the damn thing because of how discouraging it is, but every time I look at her I know I would just shoot myself in the foot if I sold it I do hate my car with a passion every time it does the hesitation but I know I will get it figured out SOMEDAY!
I do hate my car with a passion every time it does the hesitation but I know I will get it figured out SOMEDAY!
07-15-06, 08:34 PM
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I kinda just skimmed some of the posts and read the others but did you guys with the problem make sure the valve cover was tightened? Was there any oil around the spark plugs when you changed them? If not, when the engine is still warm try popping out a plug wire and check to see if there's any oil around the plugs. I'd check all of them. If there is then wait until the engine is cooled down like over night and tighten the valve cover. Or else if you really want to you can take the valve cover off and check the gasket.
07-26-06, 07:56 PM
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ok guys, a little update. so it still bucks. i did a smoke test on the engine. and there's no vacuum leaks. not even the throttle body. i have a very minor leak on a hose but it wouldnt make the whole car shake. so soon maybe by the end of this week i'll do a back pressure test on the exhaust, then see if my MAF sensor is working properly. i'm due for an oil change, so i'll probably change the air filter while i'm at it and see what happens. i checked out some technical service bulletins on our cars, and one of them said something about a knock sensor not working. i dont think this is the problem i have, but it might be for some other people. i dont know. just wanted to let you guys know about that.