I'm having a similar problem with my 88 Tempo. Did you ever get a
solution for your car?
Mine is idling at about 1000 rpm in park whether it's warm or cold. When
I put it in gear it jerks foreward like my foot was on the accelerator.
Sometimes in park it surges between 800 and 1200. I tried disconnecting
the TPS and battery to reset the memory, but even without the TPS plugged
in the engine responds equally.
I've checked the voltage on the EMI(?) and found that it read out at about
1.0. I've cleaned out everything between the air filter and the fuel
injectors. I can't find any vacuum leaks, the fuel pressure is good, no
related errors show up and backing off the idling screw would be pointless
since it isn't touching even now.
Plugs and wires have been replaced as has the fuel filter.
Anybody have ideas?