get a manual, check the pin outs on the distributor plug and ohm test the 2 wires for the crank sensors, and the other 2 sensors one is for TDC and im not sure what the other is called. the 3 sensors test the same and should read the same. the should run 300-700 ohms i believe.

if they ohm good, check your wiring at the distributor plug and check continutity from the unhooked harness plug all the way to the ecu pin outs.

in limp mode the ecu electronically limits your rpms between 3500-4000. it changes ignition so you dont fuck anything up. a faulty sensor will immediately put you in limp mode with a check engine light on,