SC430 power lost on highway.
#17
Lead Lap
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When you say that it loses power when you are driving at 60 + mph, do you mean that your speed is steady at the point of power loss or that when you attempt to accelerate at that speed that you lose power.
If it is when you attempt to accelerate that you lose speed or the engine just doesn't respond, you ought to try resetting the engine ECU. Here are the instructions for that:
If you want to reset the ECU without losing your seat and stereo settings,
perform the following procedure:
1. Get in your car and insert key. (It doesn't matter if you close the door or not.)
2. Turn the key to the on (not start) position.
3. Press the gas pedal to the floor.
4. Hold the pedal to the floor for five seconds, then turn the key back to the "off" position
(don't remove the key), then release the gas pedal.
5. Wait 2 minutes.
6. Remove key.
7. Done
If it is when you attempt to accelerate that you lose speed or the engine just doesn't respond, you ought to try resetting the engine ECU. Here are the instructions for that:
If you want to reset the ECU without losing your seat and stereo settings,
perform the following procedure:
1. Get in your car and insert key. (It doesn't matter if you close the door or not.)
2. Turn the key to the on (not start) position.
3. Press the gas pedal to the floor.
4. Hold the pedal to the floor for five seconds, then turn the key back to the "off" position
(don't remove the key), then release the gas pedal.
5. Wait 2 minutes.
6. Remove key.
7. Done
#18
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OoOo my '02 has done exactly the same thing now a few times. Driving along at 65, suddenly the pedal feels sluggish and there's no power. Pressing the gas way down maintains speed, but in general, accelerator is unresponsive. After a few minutes it's back to normal pedal response. But for those few minutes I'm looking to the right lane to see what I need to do to pull off the road
Were you able to find a fix?
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#19
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I have the same problem. Cleaning the MAF and resetting it by disconnecting the positive cable helped for a week or so but degraded again. Time for a New MAS!!
#20
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Sorry I haven't been on the forums a lot lately. I was able to get the dealer to reprogram something, I forget what it was and they also check if I had any code, but nothing.
#21
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Although Accel position sensor and throttle position sensor problems can happen on your car, if an error would occur for more than .5 seconds, a code would be set and it would shut down the system until you cycle the key.
And it can't just have a simple problem where the sensors just give the wrong readings to the ecu. the Accel position sensor and the TPS each have two internal senors built in (called potentiometers, i think that's the word someone was going for in an earlier post when the word thermistor was used). the two sensors have to agree on the pedal (or throttle) position. if they don't agree for more than .5 seconds, code and throttle shut down.
#23
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Have you replaced the FUEL FILTER? Start there first. It could be you got a bad tank of gas, perhaps contaminated by water. Water being denser than gas will sink to the bottom of the tank. The engine will idle just fine, but when it needs more gas, the pump pulls hard enough to pick up the water from the bottom of the gas tank. This wouldn't throw any codes, but would cause the problems you describe. It is where I would start if I were experiencing this problem.
#24
Lexus Test Driver
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Have you reset your ECU as desribed in an earlier post? Another foolproof option is to disconnet your battery for 30 min (ok that's overkill but works ...) but then you will have to reprogramm the radio and seats.
Myself and many member have had issues that also scewed the car's ECU driving habit memory ( so to speak). At this stage you have nothing to loose. I did that after cleaning both the MAF and TB inside and out (remove the TB) and the problem was fixed.
Worth a try.
Note even if your TB looks clean, it might be quite dirty on the inside.
Myself and many member have had issues that also scewed the car's ECU driving habit memory ( so to speak). At this stage you have nothing to loose. I did that after cleaning both the MAF and TB inside and out (remove the TB) and the problem was fixed.
Worth a try.
Note even if your TB looks clean, it might be quite dirty on the inside.
#25
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Been watching this post and wondering if this problem is still happening when you are on cruise control. If the issue doesn't show up on cruise but only when you have your foot on the pedal I would suspect the gas pedal module that is part of the gas pedal and sends a signal to the computer in turn sending a signal to your throttle body motor telling it to open the throttle. On cruise this module is bypassed thus taking your gas pedal out of the loop. Give it a try and see what happens. Changing the gas pedal is simple.
Hope this helps?
Hope this helps?
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#26
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Mine did exactly the same thing. I cleaned the MAF very very thoroughly, filled the tank and put in 2 cans of Techron Fuel Injector Cleaner, and have not had the problem since. I also stopped going to the cheap gas place, and only run Shell. Try the MAF again?
#27
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I think it could be the ECU going bad. My old isuzu trooper had problem accelerating past 50 mph and after replacing ECU it fixed the problem. Prior to that i had various warning lights going off on my dashboard and had problem moving forward one time. It as been two years since i replace the ECU and my 96 trooper is going strong.
#28
Pole Position
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I know it was mentioned before, but there there was no diagnostic done. Could this be a bad alternator and loose ground cable? I know in the past to test alternators on my other cars, the testing technique included running the car and then removing the ground from the battery. If alternator is bad, the car will sputter out. Not sure if this could happen here.
Last edited by ShawnOk; 05-15-13 at 09:29 AM.
#29
Pole Position
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Could this also be either an 02 sensor or a speed sensor? I heard that only two of the four O2 sensors will throw a code. As for the speed sensor suggestion, I had a 99 Chrylser Sebring (AT- Mitsubishi Engine) with a bad speed sensor, and the car would miss its shift points and therefore it wouldn't change into third gear and only alternated between 1st and 2nd gear depending on road speed. Possibly not able to shift into a higher gear in his case?Just a thought.
#30
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I replace the MAF and it did not help. I just resettled the ecu but I haven't drove on the freeway yet. But in the city I have not had a problem yet. I changed an o2 sensor recently also because I got a cel. I'll try to update soon. Thanks everyone for the help.