# 1990 Stanza bucking at certain rpm



## isb360 (Apr 6, 2005)

Hi all,


My 1990 Stanza 5-speed occasionally begins "bucking" above a certain RPM. Car is an XE with no tach, but it sounds like above around 2500 or 3000rpm it will start violently bucking, regardless of road speed, gear choice, or throttle position. It is strictly RPM dependant. Lower the engine revs below the magic threshhold and the problem disappears, above it and it comes back. It happens randomly, but more frequently in the summer (maybe higher humidity?) time. The (temporary) cure is always to shut the car off and start it back up again. Thankfully this can be done on the fly in short order, but still a a pain.

I've heard several possible causes through the grapevine, so am hoping for some better advice. Is it a sensor? Or the engine tripping into "safe" mode or something? Looking for a part to replace.

Thanks
Tim


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## blownb310 (Jun 10, 2002)

First have you ever replace the ignition wires and cap any time in the car's lifetime? If not try those first. 

Otherwise, I have seen the throttle position sensors wear out in a single certain spot. That spot is where the throttle spends the most time, cruising. I found the problem with a digital volt meter back probing the TPS connector. When I hit that spot the voltage dropped to zero. Replaced the TPS and the problem was solved.


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