91 maxima 3.0L (3000) ECU LOCATION & CODES
my daughters car is running rough so i did a tune on it, plugs,wires, cap. & rotor. (fyi-this has 220,000 miles on it but still runs strong just rough). still runs the same,i have a friend with a diagnostic unit but can't find were to plug in. is there a way to pull the codes to see if it is a sensor or an injector? i saw something on here about the screw on the side of the ecu?? how does this work and were is it? thanks to all who can help!