What plugs are the easiest to screw up & miss-plug on an 88/89 d15b2? Got a code 3 map sensor with erratic idle. If I by-pass the MAP, idles fine with no codes but the CEL stays on. Wondering if there is a way to make the ECU think the MAP is ok, or if I plugged something in backwards during the engine replacement. I can't afford to put anymore $ into this car. It's going up for sale as soon as it runs right. Been dinking with it for 4 months now.