Limp-in mode is third gear. There's something wrong. Beyond that you need diagnostic equipment (i.e. a dealer or well-equipped shop) to know what the problem actually is.
If the check engine light was on, you may be able to get some information by turning the key from OFF to RUN three times quickly. A selection of stored diagnostic codes will be displayed in the EVIC. Still won't give you a full picture, though.
2006 WK Laredo 4x4 4.7L
1993 ZJ Laredo 4x4 4.0L — Dead, sold, and rolling again