i have a 2000 accord 2.3L auto

runs rough, misses, stalls sometimes, etc...just runs like garbage

has codes for a misfire on 1 & 3 along with codes

P1399 - Random Cylinder Misfire Detected
P1259 - VTEC System Malfunction
P0108 - MAP Sensor Circuit High Voltage


so far we have done:

new plugs
checked wires for proper resistance
adusted valves properly to .010 intake .012 exhaust
new pcv valve



please help me, this car is very important to have running asap - classes start soon

so far im guessing bad egr and MAP sensor? what about cylinder 1 and 3 misfires?

 

The ECM monitors the MAP sensor circuit via a voltage drop in the ECM. When it sees an open in the MAP sensor circuit it fails the monitor and sets the DTC. I would suspect either a faulty MAP sensor or an open circuit in the wiring.

Checking the MAP sensor is easy. There is a 5 volt reference, a ground and a variable sensor signal voltage ( around 2.8 volts key on engine off, around .9 volts engine at hot idle ).

Honda fuel control on fuel injected vehicles relies on the MAP sensor as the primary input followed by the O2 sensors, TPS, ECT etc.

A problem with the MAP sensor circuit could cause serious drivability issues.

The misfire could be caused by numerous issues including the drivability problems surrounding the faulty MAP sensor input.

The P1259 is typically caused by low oil pressure as a result of low oil level. A clogged filter or thick or poorly maintained oil can cause this DTC as well.

I would troubleshoot the MAP sensor circuit first.