Let's go with the EGR valve possibly sticking open. Any gross vacuum leak,
including excess EGR flow, will cause the RPMs to kick up.

The fact that you had a loose battery cable probably lost some of the
adaptive settings in the ECU. This is re-learned as you drive (the 'drive
cycle') and may correct any problems after 50-100 miles.
EGR related codes (most codes for that matter) are not set in memory until
the engine is at normal operating temperature...coolant level, thermostat
and coolant temperature sensor (CTS) are responsible for this. For that
matter, an open CTS circuit often causes high idle and rich fuel mix. Check
that the CTS cable is not pinched or loose at the sensor. I've seen worn
motor mounts that allow the engine to twist and put tension on loose
harnesses.

"Buzz" > wrote in message
news
> My '96 SL single cam has 185K on the clock, and has been running fine.
> A few weeks ago I changed the oil and hosed off the motor with a
> garden hose. Then the "Service Engine" light came on, but it was
> running fine. A few days later it went off, and my buddy at work
> hooked up his code readed and said it had a EGR related code in the
> memory.
> I drove it a couple of weeks, and light stayed off. It wouldn't start
> the other day, and wiggling the battery terminals got it to start, so
> I drove it home and cleaned the terminals, which really didn't look
> bad at all, but I polished them bright with a wire wheel.
>
> The next time I drove it after the terminal cleaning, the engine had a
> high idle, and would race up to 3000 RPM when I would clutch it
> between gears. the idle would eventully settle down to 750 RPM.
> Drove it to work today, and it still would race up between gears,
> almost like I wasn't letting off the gas pedal when shifting. When I
> would put it in neutral coasting up to a stop, the engine would be at
> 2000 RPM, then slowly drop to a 750 RPM idle. No check engine light
> is coming on at this time.
>
> What could be causing this?