97 LE stalling with P0125, P0171 and P401 codes

[Jmac]

My 97 LE is constantly stalling at low RPM and throwing codes P0125, P0171 and P0401 with a check engine light. Drivable but dangerous. Any suggestions as to what the problem might be? I will likely take to a Toyota dealer, although in the past they seem to have little Previa expertise. Thanks in advance for your suggestions.

[Jmac]

Loose negative terminal caused incorrect codes to be generated. After tightening, it read codes P0300, 301-304 and 125. Spark plugs or/or ignition coil are likely problem.

[tbkilb01]

a tuneup may be in order. a little different locations but same parts... set the timing service the dizzy clean throttle body etc . but again there are other variables that can cause misfires. i even did the fuel filter and tranny filter one year but i really need to do my 92 again. its really been parked for a while.I definitely want to disconnect the oil reservoir.

[Previologist]

Loose negative terminal caused incorrect codes to be generated. After tightening, it read codes P0300, 301-304 and 125. Spark plugs or/or ignition coil are likely problem.

Or old or aftermarket wires, or injectors. I recently had a 302 on my 97 4runner and found the old wire completely rotted through. Always use OEM. Mine were OEM but I can''t remember if I've ever changed them in the last 10 years...