Tachometer Fluctuation Issue

Old 07-31-2015, 02:35 PM
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Tachometer Fluctuation Issue

I have 1998 Acura 2.5TL.
Tachometer Fluctuation issue while on highway with no visible transmission noise. Is this problem due to faulty ECU or wiring harness to the ECU. I am encountering this problem again after driving for a week or so since I last reported this issue. It feels there is acceleration issue at highway speed as if it hesitates. One of the acura mechanic I asked on "" feels it is ECU issue, Initially he told me it could be crank sensor failure, then after I gave more details, the ECU problem was hinted, Any thoughts?. I drove steady at 60 to 65 mph on highway for 1 hour, all the time the tachometer was going crazy, speedometer behaved correctly. I did get P700 code, my mechanic feels it is torque converter issue and I should give up the car. Could it be the ignitor coil in the distributor which supplies the pulse?
Today when I drove for 30 minutes on highway, the tachometer was jumping when I started the car in Idle (around 500 to 1000 rpm) without any accleration. As soon as I start driving I feel the heavy jerk on 1/2nd gear transition. Tachometer craziness continued for around 15 minutes on highway, then it disappeared and happened again after somtime. It is intermittent. When the tachometer is not jumping the car drives smoothly. I have no CEL light so far.

Last edited by mankaraja; 07-31-2015 at 02:38 PM.
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Old 09-20-2015, 10:02 AM
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Fixed the tachometer fluctuation. Replaced ignition coil together with ICM (got it for $40 from junkyard). Its been over month now. Drives beautifully. Recently changed the inner and outer tie rods. Drives even more beautifully now. Nostalgic memories of the drive 6 years ago came back. Wonderful car! Hope I pass the 3rd gate (281000 miles now)
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