'98 LS400 acceleration jumps
09-23-11, 01:42 PM
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'98 LS400 acceleration jumps
Hey Folks, as always, thanks to all! Now that I understand that I actually do have a DBW vehicle (thanks to previous posting), I have a question about a sudden acceleration problem with the car. Again, it is a 1998 LS400 V8 that had no acceleration problem until one day the starter quit. Took it to the dealer and they replaced the starter. (Thank God for 2nd mortgages!) When I got it back, I let it sit for a number of months and then brought the car out and started driving it again. I noticed that as I gently stepped down on the gas, the engine would suddenly accelerate. When I say "gently" what I mean is that I touched the gas pedal with the car in drive, which took the RPMs up to about 1,000, and the car started to move forward. Without moving the pedal any further, the RPMs jump to 1500-1700 and the car lurches forward. It is almost as thought the car comes off an idle circuit and jumps into a run circuit without moving the pedal. Has any one ever experienced this? I truly do not remember the car doing this before the starter problem. It may have but I can't remeber. I had only owned the car a couple of months before the starter quit. I can reproduce the problem every time. I do not remember the car doing this before they replaced the starter and I do understand that in order to replace the starter, they have to do some serious surgery on the engine. Does any one have any ideas? Could it be that it was always like this and I just didn't realize it? Thanks again to all!
Chris
Chris
09-23-11, 02:34 PM
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Hey Folks, as always, thanks to all! Now that I understand that I actually do have a DBW vehicle (thanks to previous posting), I have a question about a sudden acceleration problem with the car. Again, it is a 1998 LS400 V8 that had no acceleration problem until one day the starter quit. Took it to the dealer and they replaced the starter. (Thank God for 2nd mortgages!) When I got it back, I let it sit for a number of months and then brought the car out and started driving it again. I noticed that as I gently stepped down on the gas, the engine would suddenly accelerate. When I say "gently" what I mean is that I touched the gas pedal with the car in drive, which took the RPMs up to about 1,000, and the car started to move forward. Without moving the pedal any further, the RPMs jump to 1500-1700 and the car lurches forward. It is almost as thought the car comes off an idle circuit and jumps into a run circuit without moving the pedal. Has any one ever experienced this? I truly do not remember the car doing this before the starter problem. It may have but I can't remeber. I had only owned the car a couple of months before the starter quit. I can reproduce the problem every time. I do not remember the car doing this before they replaced the starter and I do understand that in order to replace the starter, they have to do some serious surgery on the engine. Does any one have any ideas? Could it be that it was always like this and I just didn't realize it? Thanks again to all!
Chris
Chris
09-26-11, 04:18 AM
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Hey Sethjon,
Thank you for the reply. Just one question that I'm stuck on. What would the transmission have to do with the RPMs jumping up all of a sudden and the car lurching forward? Thanks.
Thank you for the reply. Just one question that I'm stuck on. What would the transmission have to do with the RPMs jumping up all of a sudden and the car lurching forward? Thanks.
10-06-11, 12:00 AM
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i think the cable is installed wrong on the TB unit.
pop the cover and move the throttle cam by hand and listen for rpm changes.
does the engine spike rpms in idle as well as drive ?
pop the cover and move the throttle cam by hand and listen for rpm changes.
does the engine spike rpms in idle as well as drive ?
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jmadhuri
LS - 1st and 2nd Gen (1990-2000)
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