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dead battery then will not exceed 40mph

5 December 2009
On my 1991, the battery was dead when I went to start the car at the end of the workday. I got a jumpstart and it started easily. On the way home, I found I could not exceed 40mph in any gear. I assumed that this was a fail-safe mode, possibly caused by the dead battery. I disconnected the terminals, recharged the battery, then reconnected the terminals. The car started and ran fine, but still would not exceed 40mph under any throttle/gear positions. It was at that time I noticed that the brake lights were on and would not go off. I tried cyclying the brake switch by hand and checked the connections. The switch seems physically fine. I have ordered another brakelight switch. I assume the new switch will fix the taillight/dead battery problem, but why won't the car go over 40 mph?
Yes it sounds like fail safe mode, try reseting the ECU by removing the clock fuse for 10 seconds. Did you have a CEL or any fail indications? Your car is automatic?
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Is the plastic "stop" in place for the brakelight switch to hit? That piece sometimes cracks and falls off causing the brakelights to stay on and draining the battery.